Add missing string versions of MySQL commands

The STRPACKETTYPE macro was missing a number of the commands from the enum.

Added executed command byte value to readwritesplit info level log output.

include/maxscale/modutil.h

@@ -83,4 +83,7 @@ bool is_mysql_statement_end(const char* start, int len);
 bool is_mysql_sp_end(const char* start, int len);
 char* modutil_get_canonical(GWBUF* querybuf);
 
+// TODO: Move modutil out of the core
+const char* STRPACKETTYPE(int p);
+
 MXS_END_DECLS