[sql] QuotaDatabase schema upgrade doesn't use transactions right.

sql/connection.cc

Index: sql/connection.cc
diff --git a/sql/connection.cc b/sql/connection.cc
index 669344a30b58839600914a4a8bac342a4d47d2dd..28beafc54335d7d1d7fc307ca658f1e7bc8333ae 100644
--- a/sql/connection.cc
+++ b/sql/connection.cc
@@ -1139,7 +1139,7 @@ void Connection::RollbackTransaction() {
 
 bool Connection::CommitTransaction() {
   if (!transaction_nesting_) {
-    DLOG_IF(FATAL, !poisoned_) << "Rolling back a nonexistent transaction";
+    DLOG_IF(FATAL, !poisoned_) << "Committing back a nonexistent transaction";
     return false;
   }
   transaction_nesting_--;