AU: Resume interrupted update attempts.

BUG=7390,7520
TEST=unit tests

Change-Id: I9baf72aa444dd855409f865f03fb665e91f8d03d

Review URL: http://codereview.chromium.org/3620013
diff --git a/delta_performer_unittest.cc b/delta_performer_unittest.cc
index 5565c88..07fd8cc 100755
--- a/delta_performer_unittest.cc
+++ b/delta_performer_unittest.cc
@@ -259,6 +259,8 @@
                               manifest_metadata_size)).WillOnce(Return(true));
   EXPECT_CALL(prefs, SetInt64(kPrefsUpdateStateNextOperation, _))
       .WillRepeatedly(Return(true));
+  EXPECT_CALL(prefs, GetInt64(kPrefsUpdateStateNextOperation, _))
+      .WillOnce(Return(false));
   EXPECT_CALL(prefs, SetInt64(kPrefsUpdateStateNextDataOffset, _))
       .WillRepeatedly(Return(true));
   EXPECT_CALL(prefs, SetString(kPrefsUpdateStateSHA256Context, _))