Use crossystem rather than cros_boot_mode.

Also, make the check for normal mode a bit more restrictive.

BUG=chromium-os:13283
TEST=unit tests, tested on device

Change-Id: I3ec8a4c5526208d6f050ec2e152604b2ead76f27

Review URL: http://codereview.chromium.org/6719012
diff --git a/utils_unittest.cc b/utils_unittest.cc
index 0fda08f..67a14db 100644
--- a/utils_unittest.cc
+++ b/utils_unittest.cc
@@ -31,7 +31,7 @@
 
 TEST(UtilsTest, IsNormalBootMode) {
   // Pretty lame test...
-  EXPECT_FALSE(utils::IsNormalBootMode());
+  EXPECT_TRUE(utils::IsNormalBootMode());
 }
 
 TEST(UtilsTest, NormalizePathTest) {