hg-ssh: refactor to have main() method

Refactor hg-ssh to have a main() function instead of a bunch of
top-level statements.

contrib/hg-ssh

@@ -33,8 +33,10 b' from mercurial import dispatch'
 
 import sys, os, shlex
 
+def main():
 cwd = os.getcwd()
-allowed_paths = [os.path.normpath(os.path.join(cwd, os.path.expanduser(path)))
+    allowed_paths = [os.path.normpath(os.path.join(cwd,
+                                                   os.path.expanduser(path)))
                  for path in sys.argv[1:]]
 orig_cmd = os.getenv('SSH_ORIGINAL_COMMAND', '?')
 try:
@@ -47,7 +49,9 b" if cmdargv[:2] == ['hg', '-R'] and cmdar"
     path = cmdargv[2]
     repo = os.path.normpath(os.path.join(cwd, os.path.expanduser(path)))
     if repo in allowed_paths:
-        dispatch.dispatch(dispatch.request(['-R', repo, 'serve', '--stdio']))
+            dispatch.dispatch(dispatch.request(['-R', repo,
+                                                'serve',
+                                                '--stdio']))
     else:
         sys.stderr.write('Illegal repository "%s"\n' % repo)
         sys.exit(255)
@@ -55,3 +59,5 b' else:'
     sys.stderr.write('Illegal command "%s"\n' % orig_cmd)
     sys.exit(255)
 
+if __name__ == '__main__':
+    main()