Add catch all to common-stage-tag for unknown toolsets. It uses the first part of the toolset name as the tag.

[SVN r20544]

tools/build

@@ -1 +1 @@
-Subproject commit b5d027e5ac2e7257443762107f7c8810bcb6327f
+Subproject commit 08a13f67433180e5694abda887e10195b291af78