Improve file ordering behavior when one parameter is "." and other parameters are other directories

eg, `git-annex get . ..` used to order the files strangly, because it
did not realize that when git ls-files output eg "foo", that should be
grouped with the first set of files and not the second set.

Fixed by making            dirContains "." "./foo" = True
which makes sense, because dirContains ".." "../foo" = True

CHANGELOG

@@ -17,6 +17,8 @@ git-annex (7.20191219) UNRELEASED; urgency=medium
   * annex.addunlocked can be configured by git-annex config.
   * git-annex-config --set/--unset: No longer change the local git config
     setting, except for in the special case of annex.securehashesonly.
+  * Improve file ordering behavior when one parameter is "." and other
+    parameters are other directories.
 
  -- Joey Hess <id@joeyh.name>  Wed, 18 Dec 2019 15:12:40 -0400
 

Utility/Path.hs

@@ -113,7 +113,10 @@ prop_upFrom_basics dir
  - are all equivilant.
  -}
 dirContains :: FilePath -> FilePath -> Bool
-dirContains a b = a == b || a' == b' || (addTrailingPathSeparator a') `isPrefixOf` b'
+dirContains a b = a == b
+	|| a' == b'
+	|| (addTrailingPathSeparator a') `isPrefixOf` b'
+	|| a' == "." && normalise ("." </> b') == b'
   where
 	a' = norm a
 	b' = norm b