dotest.py - fixed a bug displaying usage

./dotest.py --help

llvm-svn: 238043
diff --git a/lldb/test/dosep.py b/lldb/test/dosep.py
index 0806074..1f73e3f 100755
--- a/lldb/test/dosep.py
+++ b/lldb/test/dosep.py
@@ -233,7 +233,10 @@
 
     is_posix = (os.name == "posix")
     dotest_argv = shlex.split(dotest_option_string, posix=is_posix) if dotest_option_string else []
-    dotest_options = dotest_args.getArguments(dotest_argv)
+
+    parser = dotest_args.create_parser()
+    dotest_options = dotest_args.parse_args(parser, dotest_argv)
+
     if not dotest_options.s:
         # no session log directory, we need to add this to prevent
         # every dotest invocation from creating its own directory