linux-testing: Update to version 3.19-rc5.

Using linux-testing for a bunch of machines, I'd actually expect it to
be more recent than the latest stable, but until now it actually was
behind.

Since torvalds/linux@464ed18ebd, the option
PM_RUNTIME doesn't exist anymore, so we need to remove it from our
common config.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/os-specific/linux/kernel/common-config.nix

@@ -6,7 +6,9 @@ with stdenv.lib;
   # Power management and debugging.
   DEBUG_KERNEL y
   PM_ADVANCED_DEBUG y
-  PM_RUNTIME y
+  ${optionalString (versionOlder version "3.19") ''
+    PM_RUNTIME y
+  ''}
   ${optionalString (versionAtLeast version "3.10") ''
     X86_INTEL_PSTATE y
   ''}