Disable poppler on Windows since it no longer compiles in VS2013

R=borenet@google.com

Author: robertphillips@google.com

Review URL: https://codereview.chromium.org/285293008

git-svn-id: http://skia.googlecode.com/svn/trunk@14764 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gyp/common_variables.gypi b/gyp/common_variables.gypi
index 033073f..61efe92 100644
--- a/gyp/common_variables.gypi
+++ b/gyp/common_variables.gypi
@@ -73,7 +73,7 @@
         }, {
           'os_posix%': 1,
         }],
-        [ 'skia_os in ["linux", "win"]', {
+        [ 'skia_os in ["linux"]', {
           'skia_poppler_enabled%': 1,
         }, {
           'skia_poppler_enabled%': 0,