Fix long-standing multimethod test error.

- New inclusive version ranges from git-fetching branch enable a fix.
- Can now write :1 to include 1.3, 1.4, etc.
  - couldn't do this before so provides() was weird.

var/spack/mock_packages/mpich/package.py

@@ -37,7 +37,7 @@ class Mpich(Package):
     version('3.0', 'foobarbaz')
 
     provides('mpi@:3', when='@3:')
-    provides('mpi@:1', when='@1:')
+    provides('mpi@:1', when='@:1')
 
     def install(self, spec, prefix):
         pass