Fix a typo when comparing the verity mode

The veritymode string used by the bootloader should be lowercase 'eio'
instead of 'EIO'. Fix the typo and change to strcasecmp.

Bug: 27175949
Change-Id: I376dacc70eef7364e2b9931a7c940adedcdb1929
diff --git a/update_verifier/update_verifier.cpp b/update_verifier/update_verifier.cpp
index f89eb5a..53e5efe 100644
--- a/update_verifier/update_verifier.cpp
+++ b/update_verifier/update_verifier.cpp
@@ -160,9 +160,9 @@
     if (property_get("ro.boot.veritymode", verity_mode, "") == -1) {
       SLOGE("Failed to get dm-verity mode");
       return -1;
-    } else if (strcmp(verity_mode, "EIO") == 0) {
+    } else if (strcasecmp(verity_mode, "eio") == 0) {
       // We shouldn't see verity in EIO mode if the current slot hasn't booted
-      // successfully before. Therefore, fail the verification when veirtymode=EIO.
+      // successfully before. Therefore, fail the verification when veritymode=eio.
       SLOGE("Found dm-verity in EIO mode, skip verification.");
       return -1;
     } else if (strcmp(verity_mode, "enforcing") != 0) {