g-ir-merge: Avoid recursive includes

Ensure the namespace is not part of the includes. This is a kludge and
shouldn't ever happen, except it does (in continuous, induced by vala).

The next big thing that would happen here is a rewrite of libtracker-sparql
vala bits so we don't need this merging anymore, so I won't put much
thought on it.
1 job for master in 2 minutes and 9 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #287011
test-fedora-latest

00:02:09