Fix build when using Xcode 7 which contains .tbd files instead of .dylib

BUG=

Review URL: https://codereview.webrtc.org/1315063005

Cr-Commit-Position: refs/heads/master@{#9866}
diff --git a/webrtc/libjingle_examples.gyp b/webrtc/libjingle_examples.gyp
index 7339cc4..abe7e8a 100755
--- a/webrtc/libjingle_examples.gyp
+++ b/webrtc/libjingle_examples.gyp
@@ -338,11 +338,9 @@
             'xcode_settings': {
               'OTHER_LDFLAGS': [
                 '-framework CFNetwork',
+                '-licucore',
               ],
             },
-            'libraries': [
-              '$(SDKROOT)/usr/lib/libicucore.dylib',
-            ],
           }
         },  # target socketrocket
       ],  # targets