Bug 1272176 - Move performance artifact schema into mozharness directory; r=wlach

Currently, only Talos accesses this file. An uncoming commit will add
a non-Talos consumer. Enable all mozharness consumers to access the
file by including it in the mozharness directory (previously it was
part of the Talos test archive).

MozReview-Commit-ID: ADlCj9E5BwC

--HG--
rename : testing/talos/treeherder-schemas/performance-artifact.json => testing/mozharness/external_tools/performance-artifact-schema.json
extra : rebase_source : ce5fcaf700941ce260c97c6daeefa07b4ef5e617

testing/mozharness/mozharness/mozilla/testing/talos.py

@@ -25,6 +25,11 @@ from mozharness.mozilla.testing.errors import TinderBoxPrintRe
 from mozharness.mozilla.buildbot import TBPL_SUCCESS, TBPL_WORST_LEVEL_TUPLE
 from mozharness.mozilla.buildbot import TBPL_RETRY, TBPL_FAILURE, TBPL_WARNING
 
+external_tools_path = os.path.join(
+    os.path.abspath(os.path.dirname(os.path.dirname(mozharness.__file__))),
+    'external_tools',
+)
+
 TalosErrorList = PythonErrorList + [
     {'regex': re.compile(r'''run-as: Package '.*' is unknown'''), 'level': DEBUG},
     {'substr': r'''FAIL: Graph server unreachable''', 'level': CRITICAL},
@@ -340,8 +345,8 @@ class Talos(TestingMixin, MercurialScript, BlobUploadMixin):
             parser.update_worst_log_and_tbpl_levels(WARNING, TBPL_WARNING)
             return
 
-        schema_path = os.path.join(self.talos_path, 'treeherder-schemas',
-                                   'performance-artifact.json')
+        schema_path = os.path.join(external_tools_path,
+                                   'performance-artifact-schema.json')
         self.info("Validating PERFHERDER_DATA against %s" % schema_path)
         try:
             with open(schema_path) as f: