tests: remove deprecated mount tests

Signed-off-by: Ruediger Meier <ruediger.meier@ga-group.nl>
tests: ignore deprecated last
build-sys: use automake's PYTHON primary for __init__.py

Actually the initial reason for this commit was to remove execute
permission from installed __init__.py.

Now after discovering automake's _PYTHON suffix we slightly cleanup
Makemodule.am and we will install byte compiled .pyc and .pyo files.

Signed-off-by: Ruediger Meier <ruediger.meier@ga-group.nl>
build-sys: fix update-potfiles script

make distcheck was broken if a user had other source files
below srcdir (e.g. in $sourcedir/mybuilddir).

Moreover autoheaders like
  libblkid/src/blkid.h
  libmount/src/libmount.h
  libsmartcols/src/libsmartcols.h
made it into POTFILES.in when srcdir = builddir and if it runs again
after make. If these headers are in Potfile.in then next out-of-tree
build from dist tarball would fail. Now we exclude (hopefully) all
of them like config.h.

Signed-off-by: Ruediger Meier <ruediger.meier@ga-group.nl>
build-sys: restore make distcheck's configure flags

They got lost with --enable-most-builds in 08b1c219.

Additionally we add --with-python but don't add --with-systemd because
there are still many systems where systemd is not available.

Would be nice to have --enable-gtk-doc too but out-of-tree build has
to be fixed first.
travis-ci: refacor and add .travis-functions.sh

Travis yaml syntax, where we can only use shell one-liners, is awful
and ugly. We add a real shell script and source it from .travis.yml.

This commit squashes a lot changings because we don't want to
pullote history with this meta CI stuff.

Highlights:
  - enable make distcheck
  - cleanup configure options (enable all progs, with python and docs)
  - shorter config.log dump
  - out-of-tree build supported
  - testing locally is possible now
  - easy to add temporary debugging stuff

Signed-off-by: Ruediger Meier <ruediger.meier@ga-group.nl>