Ensure all REST API error responses are consistent

Heat exceptions are serialized into JSON/XML responses by the fault app,
which is at the end of the WSGI pipeline. Some REST API errors however
are raised as HTTPExceptions, which are treated by WSGI as responses
ready to be sent back to the user, and they can't reach the fault app.

This patch set disguises HTTPExceptions raised by the wsgi.Resource so
they can reach the app that will serialize them just like all other
errors.

Fixes bug 1208620

Change-Id: Id98dbc1e3b208401be8f0119a6d72d4561a2221a
Fixes files with wrong bitmode

Some modules have bitmode 755. Changed to 644.

Change-Id: I4cb86987f1e2dd8420d511cb403228ba908d056b
Merge "Ensure all REST API error responses are consistent"
Merge "Fixes files with wrong bitmode"