BUG/MINOR: ssl: Undefined reference when building with OPENSSL_NO_DEPRECATED

If OPENSSL_NO_DEPRECATED is set, we get a 'error: ‘RSA_PKCS1_PADDING’
undeclared' when building jwt.c. The symbol is not deprecated, we are
just missing an include.

This was raised in GitHub issue #2098.
It does not need to be backported.
diff --git a/include/haproxy/openssl-compat.h b/include/haproxy/openssl-compat.h
index 2f6b7c2..d1fa7ba 100644
--- a/include/haproxy/openssl-compat.h
+++ b/include/haproxy/openssl-compat.h
@@ -15,6 +15,7 @@
 #include <openssl/err.h>
 #include <openssl/rand.h>
 #include <openssl/hmac.h>
+#include <openssl/rsa.h>
 #if (defined SSL_CTRL_SET_TLSEXT_STATUS_REQ_CB && !defined OPENSSL_NO_OCSP)
 #include <openssl/ocsp.h>
 #endif