Ensure SSLv3 is enabled when necessary

Either at compilation time, or as a system-wide configuration, OpenSSL
may have disabled SSLv3 protocol by default. This change ensures the
protocol NO flag is cleared when necessary, hence allowing for the
protocol to be used.

Author: Matus Honek <mhonek@redhat.com>

diff --git a/libraries/libldap/tls_o.c b/libraries/libldap/tls_o.c
--- a/libraries/libldap/tls_o.c
+++ b/libraries/libldap/tls_o.c
@@ -297,8 +297,10 @@ tlso_ctx_init( struct ldapoptions *lo, struct ldaptls *lt, int is_server )
 #endif
 	if ( lo->ldo_tls_protocol_min > LDAP_OPT_X_TLS_PROTOCOL_SSL3 )
 		SSL_CTX_set_options( ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3 );
-	else if ( lo->ldo_tls_protocol_min > LDAP_OPT_X_TLS_PROTOCOL_SSL2 )
+	else if ( lo->ldo_tls_protocol_min > LDAP_OPT_X_TLS_PROTOCOL_SSL2 ) {
 		SSL_CTX_set_options( ctx, SSL_OP_NO_SSLv2 );
+		SSL_CTX_clear_options( ctx, SSL_OP_NO_SSLv3 );
+	}
 
 	if ( lo->ldo_tls_ciphersuite &&
 		!SSL_CTX_set_cipher_list( ctx, lt->lt_ciphersuite ) )