Bug 1454876 - Install marionette.* prefs on Fennec. r=maja_zf,snorp

The marionette.* preference branch, defined in
testing/marionette/prefs/marinoette.js, controls aspects of the
Gecko remote control protocol.  Whilst Marionette is not enabled in
optimised Fennec builds, we are apparently missing these preferences
when it is built in.

The marionette.enabled preference specifically enables the remote
server to listen on a TCP port, but its default is false.

MozReview-Commit-ID: A6Q4NEQOGJR

--HG--
extra : rebase_source : 2afade62b52003e9a1578879261c7c4130047067

mobile/android/installer/package-manifest.in

@@ -370,11 +370,13 @@
 @BINPATH@/components/XPIDialogService.js
 #endif
 
+; Remote control protocol
 #ifdef ENABLE_MARIONETTE
 @BINPATH@/chrome/marionette@JAREXT@
 @BINPATH@/chrome/marionette.manifest
 @BINPATH@/components/marionette.manifest
 @BINPATH@/components/marionette.js
+@BINPATH@/defaults/pref/marionette.js
 #endif
 
 #ifdef PKG_LOCALE_MANIFEST