add tests for svn fetching.

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

@@ -0,0 +1,10 @@
+from spack import *
+
+class SvnTest(Package):
+    """Mock package that uses svn for fetching."""
+    url      = "http://www.example.com/svn-test-1.0.tar.gz"
+
+    version('svn', 'to-be-filled-in-by-test')
+
+    def install(self, spec, prefix):
+        pass