hggit: skip, not fail a test if dulwich is missing

Summary: This manifests itself on MacBooks where dulwich is not installed.

Differential Revision: D6759617

fbshipit-source-id: c90c35ebaa4fd2a14b1ad2fa0fadaca3c6ea8c29

tests/test-check-code.t

@@ -203,9 +203,6 @@ New errors are not allowed. Warnings are strongly discouraged.
   Skipping tests/test-hgsubversion-template-keywords.py it has no-che?k-code (glob)
   Skipping tests/test-hgsubversion-urls.py it has no-che?k-code (glob)
   Skipping tests/test-hgsubversion-utility-commands.py it has no-che?k-code (glob)
-  tests/test-remotenames-basic.t:308:
-   >   $ hg help bookmarks  | grep -A 3 -- '--track'
-   don't use grep's context flags
   Skipping tests/test_hgsubversion_util.py it has no-che?k-code (glob)
   [1]
 

tests/test-remotenames-basic.t

@@ -301,15 +301,14 @@ Test clone --mirror
 
 Test loading with hggit
 
+  $ . "$TESTDIR/hggit/testutil"
   $ echo "[extensions]" >> $HGRCPATH
   $ echo "hggit=" >> $HGRCPATH
   $ echo "[devel]" >> $HGRCPATH
   $ echo "all-warnings=no" >> $HGRCPATH
-  $ hg help bookmarks  | grep -A 3 -- '--track'
+  $ hg help bookmarks  | egrep -- '--(un){0,1}track'
    -t --track BOOKMARK track this bookmark or remote name
    -u --untrack        remove tracking for this bookmark
-   -a --all            show both remote and local bookmarks
-      --remote         show only remote bookmarks
 
 Test branches marked as closed are not loaded
   $ cd ../alpha