[Sync] Mark MigratePrefsAndBoolkmarkThenModifyBookmark as flaky

Test is failing on mac trybots occassionally, and have seen similar failure for
other MigratePrefs* tests

BUG=100382
TEST=sync_integration_tests
TBR=atwilson@chromium.org

Review URL: http://codereview.chromium.org/8418030

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@108152 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/sync/test/integration/migration_errors_test.cc

@@ -349,8 +349,9 @@ IN_PROC_BROWSER_TEST_F(MigrationTwoClientTest,
 
 // Triggers a server migration on two datatypes, then makes a local
 // modification to one of them.
+// Flaky. crbug.com/100382.
 IN_PROC_BROWSER_TEST_F(MigrationTwoClientTest,
-                       MigratePrefsAndBookmarksThenModifyBookmark) {
+                       FLAKY_MigratePrefsAndBookmarksThenModifyBookmark) {
   RunTwoClientMigrationTest(
       MakeList(syncable::PREFERENCES, syncable::BOOKMARKS),
       MODIFY_BOOKMARK);