Bug 1286877 - do not set c-basic-offset for python-mode; r=gps

This removes the unnecessary setting of c-basic-offset from all
python-mode files.

This was automatically generated using

    perl -pi -e 's/; *c-basic-offset: *[0-9]+//'

... on the affected files.

The bulk of these files are moz.build files but there a few others as
well.

MozReview-Commit-ID: 2pPf3DEiZqx

--HG--
extra : rebase_source : 0a7dcac80b924174a2c429b093791148ea6ac204