gitignore: add .localrc.auto and local.conf

The changeset of 893e66360caf3bcf0578d4541b3c17d089c33b02,
Change-Id of I367cadc86116621e9574ac203aafdab483d810d3
introduced local.conf and generates .localrc.auto.
But they aren't in .gitignore. This patch adds them into .gitignore.

Change-Id: I7d4dc99d980d9c5b5156cf915646bc96163a3dc4
Closes-Bug: #1267027
Merge "gitignore: add .localrc.auto and local.conf"