quiet down more third-party warnings in poppler and jsoncpp

BUG=
R=djsollen@google.com

Author: mtklein@google.com

Review URL: https://codereview.chromium.org/25319002

git-svn-id: http://skia.googlecode.com/svn/trunk@11530 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gyp/jsoncpp.gyp b/gyp/jsoncpp.gyp
index ab00db9..390f8f9 100644
--- a/gyp/jsoncpp.gyp
+++ b/gyp/jsoncpp.gyp
@@ -49,12 +49,8 @@
           '../third_party/externals/jsoncpp/include/',
         ],
       },
-      'conditions': [
-        [ 'skia_os == "android"', {
-          'cflags!': [
-            '-Wall',
-          ],
-        }],
+      'cflags': [
+        '-w',
       ],
     },
   ],