teuthology-suite: improve help for --suite-dir arg
@@ -75,7 +75,8 @@ Standard arguments:
assembling jobs from yaml fragments. This causes
<suite_branch> to be ignored for scheduling
purposes, but it will still be used for test
- running.
+ running. The <suite_dir> must have `qa/suite`
+ sub-directory.
--validate-sha1 <bool>
Validate that git SHA1s passed to -S exist.
[default: true]
