Fix unable to delete order line

Calling trigger without having globalized $conf causes error and cancels delete operation, this commit adds the missing

2014-08-23 16:52:05 ERR     127.0.0.1        Interfaces::run_triggers was called with wrong parameters action=LINEORDER_SUPPLIER_DELETE object=1 user= langs= conf=
Merge pull request #1845 from Cubexed/patch-1

Fix unable to delete order line