use mercurial instead of git on appveyor Some tests fail on git version 2.6.3.windows.1. <pre> 1) Error: GitAdapterTest#test_entries_branch: NoMethodError: undefined method `identifier' for nil:NilClass test/unit/lib/redmine/scm/adapters/git_adapter_test.rb:464:in `test_entries_branch' 2) Error: GitAdapterTest#test_entries_tag: NoMethodError: undefined method `identifier' for nil:NilClass test/unit/lib/redmine/scm/adapters/git_adapter_test.rb:447:in `test_entries_tag' </pre> git-svn-id: http://svn.redmine.org/redmine/trunk@14903 e93f8b46-1217-0410-a6f0-8f06a7374b81