hghave: be more tolerant to rst2html output
On Windows, rst2html.bat calls rst2html.py, printing something like:
"rst2html.py (Docutils"
(notice the extra ".py")
#!/bin/shhghg -qhg helphg -q helphg add -hhg add --skjdfkshg help diffhg help statushg -q help statushg help foohg skjdfksexit 0