BUG: use file name match, not regular expression 0003994

Since mrml node names may contain characters that are meaningful
in regular expressions (such as parens) use a more limited
form of matching.

From: Steve Pieper <pieper@bwh.harvard.edu>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@24255 3bd1e089-480b-0410-8dfb-8563597acbee