bug 1546945: remote: re-enable remote agent in Firefox Nightly; r=ochameau

This patch negates the effect of 004d050a8ec4 (git 6dd9496ac0f9).

Differential Revision: https://phabricator.services.mozilla.com/D28873

--HG--
extra : moz-landing-system : lando

toolkit/moz.configure

@@ -934,9 +934,14 @@ add_old_configure_assignment('FT2_CFLAGS',
 # See https://firefox-source-docs.mozilla.org/remote/ for more.
 # The source code lives under ../remote.
 
-option('--enable-cdp', help='{Enable|Disable} remote agent')
+@depends(target, milestone)
+def remote_default(target, milestone):
+    return target.os != 'Android' and milestone.is_nightly
 
-@depends('--enable-cdp')
+option('--disable-cdp', default=remote_default,
+       help='{Enable|Disable} remote agent')
+
+@depends('--disable-cdp')
 def remote(value):
     if value:
         return True