The commit "Submit Subversion directory path in Update.xml" added the
element <SVNPath>...</SVNPath> to Update.xml for Subversion work trees.
This commit teaches the CTest.UpdateSVN test to verify the presence of
the element.
This creates new tests "CTest.UpdateSVN" and "CTest.UpdateCVS". They
test that the Update.xml produced by CTest for a version-controlled
project contains entries for files added, changed, and removed.