Attempt to create HDF5 files if we fail to open them.

This step should be unnecessary as an empty file should have been created before this open call.  But apparently someone is having problems with this...

git-svn-id: svn+ssh://svn.code.sf.net/p/xmds/code/trunk/xpdeint@2910 41b19578-b77a-4e3b-9682-c8570d237623