Fix handling of --version in lit

[serge-sans-paille]

Summary

There's no reason why we should require a directory when asking for the version.

[yln]

LGTM, thanks!

llvm/utils/lit/lit/cl_arguments.py

def parse_args():
     parser.add_argument('test_paths',
             nargs='+',
             metavar="TEST_PATH",
             help='File or path to include in the test suite')
 
     parser.add_argument("--version",
             dest="show_version",
             help="Show version and exit",
-            action="store_true")
+            version="lit " + lit.__version__,
+            action="version")
+
     parser.add_argument("-j", "--threads", "--workers",
             dest="workers",
             metavar="N",
             help="Number of workers used for testing",
             type=_positive_int,
             default=lit.util.detectCPUs())
     parser.add_argument("--config-prefix",
             dest="configPrefix",

llvm/utils/lit/lit/main.py

 import lit.run
 import lit.Test
 import lit.util
 
 
 def main(builtin_params={}):
     opts = lit.cl_arguments.parse_args()
 
-    if opts.show_version:
-        print("lit %s" % lit.__version__)
-        return
-
     params = create_params(builtin_params, opts.user_params)
     is_windows = platform.system() == 'Windows'
 
     lit_config = lit.LitConfig.LitConfig(
         progname=os.path.basename(sys.argv[0]),
         path=opts.path,
         quiet=opts.quiet,
         useValgrind=opts.useValgrind,

llvm/utils/lit/tests/version.py

+# Basic sanity check that --version works.
+#
+# RUN: %{lit} --version | FileCheck %s
+#
+# CHECK: lit {{[0-9]+\.[0-9]+\.[0-9]+[a-zA-Z0-9]*}}