Revert 6380 "Replace libjingle_root with talk_root variable."

It turns out this doesn't fix the problem we're trying to solve...

> Replace libjingle_root with talk_root variable.
> 
> This CL is similar to https://review.webrtc.org/9019004/
> It is needed in order to be able to build with different
> copies of libjingle. Having the libjingle_root variable didn't
> make this possible, since relative paths in the .isolate files
> ended up at the wrong directory level and .isolate files doesn't
> support all the normal GYP variables like <(DEPTH).
> 
> BUG=chromium:343106
> TEST=trybots passing compile step with clobber.
> R=tommi@webrtc.org, wu@webrtc.org
> 
> Review URL: https://webrtc-codereview.appspot.com/15709004

TBR=kjellander@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/14669004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6384 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/all.gyp b/all.gyp
index a399a78..bd8ee13 100644
--- a/all.gyp
+++ b/all.gyp
@@ -8,7 +8,7 @@
 
 {
   'variables': {
-    'talk_root%': '<(DEPTH)/talk',
+    'libjingle_root%': '<(DEPTH)',
   },
   'targets': [
     {
@@ -17,9 +17,9 @@
       'dependencies': [
         'third_party/openmax_dl/dl/dl.gyp:*',
         'webrtc/webrtc.gyp:*',
-        '<(talk_root)/libjingle.gyp:*',
-        '<(talk_root)/libjingle_examples.gyp:*',
-        '<(talk_root)/libjingle_tests.gyp:*',
+        '<(libjingle_root)/talk/libjingle.gyp:*',
+        '<(libjingle_root)/talk/libjingle_examples.gyp:*',
+        '<(libjingle_root)/talk/libjingle_tests.gyp:*',
       ],
       'conditions': [
         ['OS=="android"', {