Fixes #2443 Zero size arrays are an extension
Merge pull request #2444 from libgit2/phkelley/flexarray

Fixes #2443 Zero size arrays are an extension
checkout::conflict tests: only test owner mode

The checkout::conflict type conflict tests were failing because
they were overly assertive about the resultant mode, testing
group & other bits, which failed miserably for people who had a
umask less restrictive than 022.  Only test the resultant owner bits.
Merge pull request #2445 from ethomson/checkout_conflict_test

checkout::conflict tests: only test owner mode