prepush: fix bug in warning message selection
In certain situations you would be told "you should pull and merge" even when
there is nothing to pull.
#!/usr/bin/env pythonimporterrno,os,sysforfinsys.argv[1:]:try:printf,'->',os.readlink(f)exceptOSError,err:iferr.errno!=errno.EINVAL:raiseprintf,'not a symlink'sys.exit(0)