Move Linux pkg-config dependencies from atom-shell to brightray.

atom.gyp

@@ -587,10 +587,6 @@
               '-rpath \$$ORIGIN',
               # Make native module dynamic loading work.
               '-rdynamic',
-              '<!@(pkg-config --libs-only-L --libs-only-other dbus-1 x11 xrandr xext gconf-2.0)',
-            ],
-            'libraries': [
-              '<!@(pkg-config --libs-only-l dbus-1 x11 xrandr xext gconf-2.0)',
             ],
           },
           # Required settings of using breakpad.

vendor/brightray

@@ -1 +1 @@
-Subproject commit 313defa8a49c45250014e7c4ec2275d50dfd490d
+Subproject commit 40ad83fb158c9be1e0df277d19794c33fd80ff28