csv_import.php addObject function small bug

Added  (strlen($ifName ) > 0)  as a verification since adding an object without ports would fail otherwise.

Doing the verification via the count of $ifName doesn't filter my tests of objects without ports.

"OBJECT;PATCHPANEL;this is a test entry; this is a test entry"
would fail without the added verification.
Merge pull request #2 from dpina000/master

csv_import.php addObject function small bug