Add 'repo version' to describe what code we are running

I meant to have this in here, so clients can more easily report
what version of repo they are running.

Signed-off-by: Shawn O. Pearce <sop@google.com>

subcmds/version.py

@@ -0,0 +1,35 @@
+#
+# Copyright (C) 2009 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import sys
+from command import Command
+from git_command import git
+from project import HEAD
+
+class Version(Command):
+  common = False
+  helpSummary = "Display the version of repo"
+  helpUsage = """
+%prog
+"""
+
+  def Execute(self, opt, args):
+    rp = self.manifest.repoProject
+    rem = rp.GetRemote(rp.remote.name)
+
+    print 'repo version %s' % rp.work_git.describe(HEAD)
+    print '       (from %s)' % rem.url
+    print git.version().strip()
+    print 'Python %s' % sys.version