Bug 1157823 - Update dependency to reflect that the marionette client requires a more recent mozhttpd. r=ato

--HG--
extra : rebase_source : 78eaacf35f6d42f6996d66b1798dee4b4e8c576f

testing/marionette/client/requirements.txt

@@ -1,7 +1,7 @@
 marionette-transport >= 0.4
 marionette-driver >= 0.4
 manifestparser >= 1.1
-mozhttpd >= 0.5
+mozhttpd >= 0.7
 mozinfo >= 0.7
 mozprocess >= 0.9
 mozrunner >= 6.2