Manually generate dependencies for *_h.swg files, so that we generate the same output whether or not they are around.
Manually generate dependencies for *_h.swg files, so that we generate the
same output whether or not they are around.

* build/generator/gen_base.py
  (IncludeDependencyInfo._scan_for_includes): Manually generate dependencies
  for *_h.swg files.

Suggested by: maxb

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion