Fix dependencies and build-time commands

Now create_manpage is not triggered during build and shoulb be
explicitly invoked.

Change-Id: I380ab8869ba24bc70965465f85eeb870ecb1dd62

create_manpage.py

@@ -130,5 +130,3 @@ class ManPageFormatter(argparse.ArgumentDefaultsHelpFormatter):
     def format_usage(self, usage):
         return ManPageFormatter._markup(usage)
 
-
-build.sub_commands.append(('create_manpage', None))

setup.py

@@ -44,7 +44,10 @@ setup(
                                           'git_upstream', 'scripts',
                                           'rebase-editor.py')],
     packages=find_packages(exclude=['test']),
-    install_requires=['GitPython'],
+    install_requires=['GitPython>=0.3.2.RC1'],
+    extras_require = {
+        'autocomplete':  ['argcomplete']
+    },
     long_description=read('README'),
     cmdclass={'create_manpage': CreateManpage},
     classifiers=[