MXS-1536: Fix crash in CREATE TABLE

If a CREATE TABLE statement had a quoted keyword as the name of a field,
the calculated column count and actual column counts would differ.

In addition to this, oneline comments before the end of the statement
would truncate the SQL due to the fact that the whitespace was squashed
before the comment removal was done.

server/modules/routing/avrorouter/avro_file.c

@@ -1008,13 +1008,13 @@ void handle_query_event(AVRO_INSTANCE *router, REP_HEADER *hdr, int *pending_tra
     memcpy(db, (char*) ptr + PHDR_OFF + vblklen, dblen);
     db[dblen] = 0;
 
-    unify_whitespace(sql, len);
     size_t sqlsz = len, tmpsz = len;
     char *tmp = MXS_MALLOC(len);
     MXS_ABORT_IF_NULL(tmp);
     remove_mysql_comments((const char**)&sql, &sqlsz, &tmp, &tmpsz);
     sql = tmp;
     len = tmpsz;
+    unify_whitespace(sql, len);
 
     if (is_create_table_statement(router, sql, len))
     {