MINOR: ssl: disable SSL sample fetches when unsupported

Previously these fetches would return empty results when HAProxy was
compiled
without the requisite SSL support. This results in confusion and problem
reports from people who unexpectedly encounter the behavior.
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index db9d4c1..248db77 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -6868,10 +6868,10 @@
  * This function is also usable on backend conn if the fetch keyword 5th
  * char is 'b'.
  */
+#if OPENSSL_VERSION_NUMBER > 0x0090800fL
 static int
 smp_fetch_ssl_fc_session_id(const struct arg *args, struct sample *smp, const char *kw, void *private)
 {
-#if OPENSSL_VERSION_NUMBER > 0x0090800fL
 	struct connection *conn = (kw[4] != 'b') ? objt_conn(smp->sess->origin) :
 	                                    smp->strm ? cs_conn(objt_cs(smp->strm->si[1].end)) : NULL;
 	SSL_SESSION *ssl_sess;
@@ -6891,15 +6891,14 @@
 		return 0;
 
 	return 1;
-#else
-	return 0;
-#endif
 }
+#endif
+
 
+#ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME
 static int
 smp_fetch_ssl_fc_sni(const struct arg *args, struct sample *smp, const char *kw, void *private)
 {
-#ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME
 	struct connection *conn;
 
 	smp->flags = SMP_F_CONST;
@@ -6915,10 +6914,8 @@
 
 	smp->data.u.str.len = strlen(smp->data.u.str.str);
 	return 1;
-#else
-	return 0;
-#endif
 }
+#endif
 
 static int
 smp_fetch_ssl_fc_cl_bin(const struct arg *args, struct sample *smp, const char *kw, void *private)
@@ -7011,10 +7008,10 @@
 #endif
 }
 
+#if OPENSSL_VERSION_NUMBER > 0x0090800fL
 static int
 smp_fetch_ssl_fc_unique_id(const struct arg *args, struct sample *smp, const char *kw, void *private)
 {
-#if OPENSSL_VERSION_NUMBER > 0x0090800fL
 	struct connection *conn = (kw[4] != 'b') ? objt_conn(smp->sess->origin) :
 	                                    smp->strm ? cs_conn(objt_cs(smp->strm->si[1].end)) : NULL;
 	int finished_len;
@@ -7043,10 +7040,8 @@
 	smp->data.type = SMP_T_BIN;
 
 	return 1;
-#else
-	return 0;
-#endif
 }
+#endif
 
 /* integer, returns the first verify error in CA chain of client certificate chain. */
 static int
@@ -8642,7 +8637,9 @@
 	{ "ssl_bc_protocol",        smp_fetch_ssl_fc_protocol,    0,                   NULL,    SMP_T_STR,  SMP_USE_L5SRV },
 	{ "ssl_bc_unique_id",       smp_fetch_ssl_fc_unique_id,   0,                   NULL,    SMP_T_BIN,  SMP_USE_L5SRV },
 	{ "ssl_bc_use_keysize",     smp_fetch_ssl_fc_use_keysize, 0,                   NULL,    SMP_T_SINT, SMP_USE_L5SRV },
+#if OPENSSL_VERSION_NUMBER > 0x0090800fL
 	{ "ssl_bc_session_id",      smp_fetch_ssl_fc_session_id,  0,                   NULL,    SMP_T_BIN,  SMP_USE_L5SRV },
+#endif
 	{ "ssl_c_ca_err",           smp_fetch_ssl_c_ca_err,       0,                   NULL,    SMP_T_SINT, SMP_USE_L5CLI },
 	{ "ssl_c_ca_err_depth",     smp_fetch_ssl_c_ca_err_depth, 0,                   NULL,    SMP_T_SINT, SMP_USE_L5CLI },
 	{ "ssl_c_der",              smp_fetch_ssl_x_der,          0,                   NULL,    SMP_T_BIN,  SMP_USE_L5CLI },
@@ -8682,10 +8679,16 @@
 	{ "ssl_fc_alpn",            smp_fetch_ssl_fc_alpn,        0,                   NULL,    SMP_T_STR,  SMP_USE_L5CLI },
 #endif
 	{ "ssl_fc_protocol",        smp_fetch_ssl_fc_protocol,    0,                   NULL,    SMP_T_STR,  SMP_USE_L5CLI },
+#if OPENSSL_VERSION_NUMBER > 0x0090800fL
 	{ "ssl_fc_unique_id",       smp_fetch_ssl_fc_unique_id,   0,                   NULL,    SMP_T_BIN,  SMP_USE_L5CLI },
+#endif
 	{ "ssl_fc_use_keysize",     smp_fetch_ssl_fc_use_keysize, 0,                   NULL,    SMP_T_SINT, SMP_USE_L5CLI },
+#if OPENSSL_VERSION_NUMBER > 0x0090800fL
 	{ "ssl_fc_session_id",      smp_fetch_ssl_fc_session_id,  0,                   NULL,    SMP_T_BIN,  SMP_USE_L5CLI },
+#endif
+#ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME
 	{ "ssl_fc_sni",             smp_fetch_ssl_fc_sni,         0,                   NULL,    SMP_T_STR,  SMP_USE_L5CLI },
+#endif
 	{ "ssl_fc_cipherlist_bin",  smp_fetch_ssl_fc_cl_bin,      0,                   NULL,    SMP_T_STR,  SMP_USE_L5CLI },
 	{ "ssl_fc_cipherlist_hex",  smp_fetch_ssl_fc_cl_hex,      0,                   NULL,    SMP_T_BIN,  SMP_USE_L5CLI },
 	{ "ssl_fc_cipherlist_str",  smp_fetch_ssl_fc_cl_str,      0,                   NULL,    SMP_T_STR,  SMP_USE_L5CLI },