Switch jsoncpp DEPS to github mirror

This change should be no-op.  It simply changes the sha1
for jsoncpp to match the commit in the github repo rather
than the git-svn mirror we previously used.  The sha1
differs simply because the git-svn metadata was not used
when they migrated to github. The tree contents are
identical (the two commits have the same tree sha1).

BUG=472809

Review URL: https://codereview.chromium.org/1069163002

Cr-Commit-Position: refs/heads/master@{#324477}

diff --git a/DEPS b/DEPS
index 4e25c81e..9c871fb 100644
--- a/DEPS
+++ b/DEPS

@@ -240,7 +240,7 @@
     Var('chromium_git') + '/external/webrtc/deps/third_party/openmax.git' + '@' +  Var('openmax_dl_revision'),
 
   'src/third_party/jsoncpp/source':
-    Var('chromium_git') + '/external/jsoncpp/jsoncpp.git' + '@' + 'ab1e40f3bce061ea6f9bdc60351d6cde2a4f872b', # from svn 248
+    Var('chromium_git') + '/external/github.com/open-source-parsers/jsoncpp.git' + '@' + 'f572e8e42e22cfcf5ab0aea26574f408943edfa4', # from svn 248
 
   'src/third_party/libyuv':
     Var('chromium_git') + '/external/libyuv.git' + '@' + 'd204db647e591ccf0e2589236ecea90330d65a66', # from svn revision 1171