Updating project.pbxproj

Cocoapods updated this file and it wasn't checked into a prior commit.
Cleanup linker flags.
Merge pull request #2504 from wordpress-mobile/issue/2503-CleanupLinkerFlags

Cleanup linker flags.
Merge remote-tracking branch 'origin/develop' into issues/2317-update-comments-page

Conflicts:
	WordPress/WordPress.xcodeproj/project.pbxproj