BUILD: ssl: fix build without OPENSSL_NO_ENGINE

The CI revealed that the boringssl build is still broken because of some
ifdef misplacement.

Bug introduced by dad3105 ("REORG: ssl: move ssl configuration to
cfgparse-ssl.c").

No backport needed.

Fix issue #633.
diff --git a/src/cfgparse-ssl.c b/src/cfgparse-ssl.c
index a3ce299..374ca92 100644
--- a/src/cfgparse-ssl.c
+++ b/src/cfgparse-ssl.c
@@ -121,7 +121,6 @@
 	return 0;
 }
 
-#ifndef OPENSSL_NO_ENGINE
 /* parse the "ssl-mode-async" keyword in global section.
  * Returns <0 on alert, >0 on warning, 0 on success.
  */
@@ -139,6 +138,7 @@
 #endif
 }
 
+#ifndef OPENSSL_NO_ENGINE
 /* parse the "ssl-engine" keyword in global section.
  * Returns <0 on alert, >0 on warning, 0 on success.
  */