Bug #13115401: -SSL-KEY VALUE IS NOT VALIDATED AND IT ALLOWS INSECURE

CONNECTIONS IF SPE

Problem description: -ssl-key value is not validated, you can assign any bogus 
text to --ssl-key and it is not verified that it exists, and more importantly, 
it allows the client to connect to mysqld.

Fix: Added proper validations checks for --ssl-key.

Note:
1) Documentation changes require for 5.1, 5.5, 5.6 and trunk in the sections
   listed below and the details are :

 http://dev.mysql.com/doc/refman/5.6/en/ssl-options.html#option_general_ssl
    and
 REQUIRE SSL section of
 http://dev.mysql.com/doc/refman/5.6/en/grant.html

2) Client having with option '--ssl', should able to get ssl connection. This 
will be implemented as part of separate fix in 5.6 and trunk.

mysql-test/t/openssl_1.test

@@ -73,22 +73,28 @@ drop table t1;
 # a different cacert
 #
 --exec echo "this query should not execute;" > $MYSQLTEST_VARDIR/tmp/test.sql
+--replace_regex /2026 SSL connection error.*/2026 SSL connection error: xxxx/
 --error 1
 --exec $MYSQL_TEST --ssl-ca=$MYSQL_TEST_DIR/std_data/untrusted-cacert.pem --max-connect-retries=1 < $MYSQLTEST_VARDIR/tmp/test.sql 2>&1
+--echo
 
 #
 # Test that we can't open connection to server if we are using
 # a blank ca
 #
+--replace_regex /2026 SSL connection error.*/2026 SSL connection error: xxxx/
 --error 1
 --exec $MYSQL_TEST --ssl-ca= --max-connect-retries=1 < $MYSQLTEST_VARDIR/tmp/test.sql 2>&1
+--echo
 
 #
 # Test that we can't open connection to server if we are using
 # a nonexistent ca file
 #
+--replace_regex /2026 SSL connection error.*/2026 SSL connection error: xxxx/
 --error 1
 --exec $MYSQL_TEST --ssl-ca=nonexisting_file.pem --max-connect-retries=1 < $MYSQLTEST_VARDIR/tmp/test.sql 2>&1
+--echo
 
 #
 # Test that we can't open connection to server if we are using