Fix request #6794 After tracker creation, no default tracker color

Change-Id: I579cb19cb51d7f9a1cc5b6f39508a52eee974475
Merge commit 'refs/changes/74/2374/1' of http://gerrit.tuleap.net/tuleap into HEAD

* http://gerrit.tuleap.net/tuleap:
  Fix request #6794 After tracker creation, no default tracker color

Change-Id: Ic92f0e82f18bdddc52abb4faddd644a0579cea61
This is Tuleap 6.12.99.105

Change-Id: I5e204727bf8ebe80d48d04dfcff47cf2ee62ab60