Xfailed test_call_log_all_calls due to bug 897036

Bug 897036 - Dialer app remains at 10% loading when test_call_log_all_calls is run
https://bugzilla.mozilla.org/show_bug.cgi?id=897036

this is reproducible on master too:
https://bugzilla.mozilla.org/show_bug.cgi?id=897036#c11
http://qa-selenium.mv.mozilla.com:8080/job/b2g.unagi.mozril.gaia.master.ui/152/HTML_Report/?