Remove duplicate hook 00-disable-apt-recommends

A recent commit into the openstack/diskimage-builder project
disallows overriding of hooks.
(Ic2c46835b27c9319f7a889ffd0ccf3f5ccc1f0cd)

A duplicate hook (00-disable-apt-recommends) has existed 
in the trove image elements, and is now causing image 
builds to fail. This duplicate hook should be removed.

Change-Id: I898721b72b195d3a4d8be8d4bc5363f16249ed85
Closes-Bug: #1383467