Fix wrong key indexes in package verification logs.

If the verification fails with the key, 'continue' will be performed and
the increment of the index at the end of the loop will be skipped.
This CL fixes it.

Test: check the log and see correct key indexes.
Change-Id: I3d1b2b8b4189f5fedbf8828f5e8e0d0b2e277c6a
diff --git a/otautil/verifier.cpp b/otautil/verifier.cpp
index 92b9faf..8a65566 100644
--- a/otautil/verifier.cpp
+++ b/otautil/verifier.cpp
@@ -257,8 +257,8 @@
 
   // Check to make sure at least one of the keys matches the signature. Since any key can match,
   // we need to try each before determining a verification failure has happened.
-  size_t i = 0;
-  for (const auto& key : keys) {
+  for (size_t i = 0; i < keys.size(); i++) {
+    const auto& key = keys[i];
     const uint8_t* hash;
     int hash_nid;
     switch (key.hash_len) {
@@ -296,7 +296,6 @@
     } else {
       LOG(INFO) << "Unknown key type " << key.key_type;
     }
-    i++;
   }
 
   if (need_sha1) {