Remove all references to 'OpenGEM'

[larsbutler]

Somehow we missed a bunch of these:

$ grep "OpenGEM" -Rn .

./bin/openquake:54:flags.DEFINE_string('config_file', 'openquake-config.gem', 'OpenGEM configuration file')
./build.xml:32:
./celeryconfig.py:22:Config for all installed OpenGEM binaries and modules.
Binary file ./celeryconfig.pyc matches
Binary file ./docs/build/doctrees/environment.pickle matches
./docs/make.bat:91: echo.^> qcollectiongenerator %BUILDDIR%\qthelp\OpenGEM.qhcp
./docs/make.bat:93: echo.^> assistant -collectionFile %BUILDDIR%\qthelp\OpenGEM.ghc
./docs/Makefile:75: @echo "# qcollectiongenerator $(BUILDDIR)/qthelp/OpenGEM.qhcp"
./docs/Makefile:77: @echo "# assistant -collectionFile $(BUILDDIR)/qthelp/OpenGEM.qhc"
./docs/Makefile:84: @echo "# mkdir -p $$HOME/.local/share/devhelp/OpenGEM"
./docs/Makefile:85: @echo "# ln -s $(BUILDDIR)/devhelp $$HOME/.local/share/devhelp/OpenGEM"
./docs/schema/README.rst:2:OpenGEM NRML schema
./docs/source/conf.py:18:# OpenGEM documentation build configuration file, created by
./docs/source/conf.py:187:htmlhelp_basename = 'OpenGEMdoc'
./docs/source/conf.py:202: ('index', 'OpenGEM.tex', u'OpenQuake Documentation',
./fabfile.py:144: print "OpenGEM deployment."

[larsbutler]

Resolved by this patch: https://github.com/gem/openquake/pull/238