Remote poller installer should test version of cacti and new poller

[xmacan]

From forum - user tried install new remote poller without success. Problem was that primary poller is older cacti version than new remote poller. Errors can occur ( DBCALL ERROR: SQL Save on table 'poller': Column 'dbretries' does not exist, unable to save!, ...)

Installer has access to primary cacti so installer should by compare version and stop installation with warning message when versions are different