Bug 1547997 Increase android max connections from 20 to 40 r=mayhemer

The Android preferences limit network.http.max-connections to 20 (set ~7 years ago).
See https://searchfox.org/mozilla-central/rev/f8b11433159cbc9cc80500b3e579d767473fa539/mobile/android/app/mobile.js#102

By removing this preference the android builds will use the all.js android preference, now set to 40.

Differential Revision: https://phabricator.services.mozilla.com/D29368

--HG--
extra : rebase_source : 3c1f9749b549119329973dda6c5c3e48e79e911e

mobile/android/app/mobile.js

@@ -98,7 +98,6 @@ pref("network.protocol-handler.warn-external.vnd.youtube", false);
 
 /* http prefs */
 pref("network.http.keep-alive.timeout", 109);
-pref("network.http.max-connections", 20);
 pref("network.http.max-persistent-connections-per-server", 6);
 pref("network.http.max-persistent-connections-per-proxy", 20);
 

modules/libpref/init/all.js

@@ -1549,7 +1549,7 @@ pref("network.http.response.timeout", 300);
 // Note: the socket transport service will clamp the number below this if the OS
 // cannot allocate that many FDs
 #ifdef ANDROID
-pref("network.http.max-connections", 256);
+pref("network.http.max-connections", 40);
 #else
 pref("network.http.max-connections", 900);
 #endif