Bug 1465181 - [run-task] Remove requirement to run as root on POSIX s…

…ystems, r=gps

There is a superficial check in the run-task script which requires root. Simply
removing this check allows a native-engine task (which isn't running as root)
to proceed.

MozReview-Commit-ID: 44XavXAwxxn

--HG--
extra : rebase_source : bd1f01ce1c2feb4029838e07314493d449a4f46e

taskcluster/scripts/run-task

@@ -506,18 +506,13 @@ def main(args):
     if 'HG_STORE_PATH' in os.environ:
         os.environ['HG_STORE_PATH'] = os.path.expanduser(os.environ['HG_STORE_PATH'])
 
-    if IS_POSIX:
-        if running_as_root:
-            user, group, gids = get_posix_user_group(args.user, args.group)
-            uid = user.pw_uid
-            gid = group.gr_gid
-        else:
-            print('error: run-task must be run as root on POSIX platforms')
-            return 1
-    else:
-        uid = gid = gids = None
+    uid = gid = gids = None
+    if IS_POSIX and running_as_root:
+        user, group, gids = get_posix_user_group(args.user, args.group)
+        uid = user.pw_uid
+        gid = group.gr_gid
 
-    if os.path.exists("/dev/kvm"):
+    if running_as_root and os.path.exists("/dev/kvm"):
         # Ensure kvm permissions for worker, required for Android x86
         st = os.stat("/dev/kvm")
         os.chmod("/dev/kvm", st.st_mode | 0o666)