Unescape branch names in compare commit
The upgrade in GitLab v7.9 to Rails v4.1.9 caused all branch names in the compare commit mode to be escaped (e.g. / to %2F). The compare mode would not always work when comparing against branch names with a forward slash.
Opted to unescape the branch name rather than use a wildcard segment to prevent escaping slashes because it seems like a more sensible URL. The slashes in this case aren't really represented by a tree structure (e.g. /compare/one/two/branch..another/branch/here).