Adding to .gitignore file

'*.swo' is another common VIM swapfile name. '*~' is used for backups
when editing files, and 'pip-wheel-metadata/' may be automatically
generated when running the application, so they belong in this file.

.gitignore

@@ -11,12 +11,15 @@ pagure_env/
 # Other python/editor specific files to ignore
 dist/
 build/
+pip-wheel-metadata/
 *.pyc
 *.pyo
+*.swo
 *.swp
 *.egg-info
 *.conf
 .coverage
+*~
 
 # Ignore files generated by run_ci_tests
 pep8.out