CHANGE: Clean the FC_FileAncestors table when removing a file

Until of now, when a file was removed from the FC, the ancestor/daughter
relationships where broken. Now simply remove the file also from that
table. Don't change the depths. Needs testing (will do).

Addresses #1190
CHANGE: Also remove the Ancestor relations if the file insertion fails
CHANGE: Fix the connectyion keyword
Merge pull request #1446 from sposs/AncestorFixing

CHANGE: Clean the FC_FileAncestors table when removing a file