Added test for Mercurial fetching.

var/spack/mock_packages/hg-test/package.py

@@ -0,0 +1,10 @@
+from spack import *
+
+class HgTest(Package):
+    """Test package that does fetching with mercurial."""
+    homepage = "http://www.hg-fetch-example.com"
+
+    version('hg', hg='to-be-filled-in-by-test')
+
+    def install(self, spec, prefix):
+        pass

var/spack/packages/lwm2/package.py

@@ -7,7 +7,7 @@ class Lwm2(Package):
     """
     homepage = "https://jay.grs.rwth-aachen.de/redmine/projects/lwm2"
 
-    version('torus', hg='https://jay.grs.rwth-aachen.de/hg/lwm2', branch='torus')
+    version('torus', hg='https://jay.grs.rwth-aachen.de/hg/lwm2', revision='torus')
 
     depends_on("papi")
     depends_on("mpi")