Remove unused .arcconfig
Remove unused .arcconfig

Added in d26829a, but never used.

Change-Id: Ibf4973cefa0de7f3df9dae703cecb3a6586cffd6

wikimedia/mediawiki-vagrant,wikimedia/mediawiki-vagrant,wikimedia/mediawiki-vagrant,wikimedia/mediawiki-vagrant,wikimedia/mediawiki-vagrant,wikimedia/mediawiki-vagrant