osg-build 1.7.0

• Add three-way diff functionality (--diff3 or -3) to osg-import-srpm
• Make osg-build log messages look nicer by replacing the
  LOGLEVEL:osg-build: prefix with a plain >>
• Remove broken test_mock_auto_cfg
• Tweak language in osg-import-srpm when creating *.source files

(SOFTWARE-2422)