Removed the logic to disable/enable GC before methods

https://bugzilla.redhat.com/show_bug.cgi?id=1138345

GC was being disabled before starting automate methods and
renabled at the end of the method. This causes some methods to
use up all the memory terminating the automate worker

GC disable/enable was added around automate methods because Ruby
would GC the objects that are returned to the method. This was changed
in the past to add a drb_return which would cache the object before
passing it to the method. Since we have a drb_return now for cached
objects we dont need to disable/enable GC anymore.
Merge pull request #973 from mkanoor/bugzilla_1138345

Removed the logic to disable/enable GC around automate methods