changed protocol_compression_level default to (-1 to 9 )

lib/MySQL_Thread.cpp

@@ -2270,7 +2270,7 @@ char ** MySQL_Threads_Handler::get_variables_list() {
 		VariablesPointers_int["client_host_error_counts"]      = make_tuple(&variables.client_host_error_counts,      0,      1024*1024, false);
 		VariablesPointers_int["handle_warnings"]			   = make_tuple(&variables.handle_warnings,				  0,			  1, false);
 		VariablesPointers_int["evaluate_replication_lag_on_servers_load"] = make_tuple(&variables.evaluate_replication_lag_on_servers_load, 0, 1, false);
-		VariablesPointers_int["protocol_compression_level"]    = make_tuple(&variables.protocol_compression_level,    0,      9,         false);
+		VariablesPointers_int["protocol_compression_level"]    = make_tuple(&variables.protocol_compression_level,   -1,              9, false);
 
 		// logs
 		VariablesPointers_int["auditlog_filesize"]     = make_tuple(&variables.auditlog_filesize,    1024*1024, 1*1024*1024*1024, false);