Fix FTBFS from prior commit.

Signed-off-by: Slávek Banko <slavek.banko@axis.cz>
(cherry picked from commit aae0287741)

src/sql/drivers/mysql/qsql_mysql.cpp

@@ -542,11 +542,11 @@ bool TQMYSQLDriver::open( const TQString& db,
 
     if (clientOptionFlags & CLIENT_SSL) {
 	mysql_ssl_set(d->mysql,
-	    ssl_key.isEmpty()? static_cast<const char *>(0):ssl_key.local8Bit(),
+	    ssl_key.isEmpty()? static_cast<const char *>(0):ssl_key.local8Bit().data(),
-	    ssl_cert.isEmpty()? static_cast<const char *>(0):ssl_cert.local8Bit(),
+	    ssl_cert.isEmpty()? static_cast<const char *>(0):ssl_cert.local8Bit().data(),
-	    ssl_ca.isEmpty()? static_cast<const char *>(0):ssl_ca.local8Bit(),
+	    ssl_ca.isEmpty()? static_cast<const char *>(0):ssl_ca.local8Bit().data(),
-	    ssl_capath.isEmpty()? static_cast<const char *>(0):ssl_capath.local8Bit(),
+	    ssl_capath.isEmpty()? static_cast<const char *>(0):ssl_capath.local8Bit().data(),
-	    ssl_cipher.isEmpty()? static_cast<const char *>(0):ssl_cipher.local8Bit()
+	    ssl_cipher.isEmpty()? static_cast<const char *>(0):ssl_cipher.local8Bit().data()
 	);
     }
     mysql_options(d->mysql, MYSQL_OPT_RECONNECT, &reconnect);