Running queries counter leaks queries
Queries that fail before they get to run cause the running queries counter to increment but never decrement. This is caused by 516801ab482c9189344304b97ff4e4429488dfc7, which calls queryStarted but not queryStopped.

diff --git a/presto-main/src/main/java/com/facebook/presto/execution/SqlQueryManager.java b/presto-main/src/main/java/com/facebook/presto/execution/SqlQueryManager.java
index c2fa751646..43f442ff32 100644
--- a/presto-main/src/main/java/com/facebook/presto/execution/SqlQueryManager.java
+++ b/presto-main/src/main/java/com/facebook/presto/execution/SqlQueryManager.java
@@ -421,6 +421,7 @@ public class SqlQueryManager
                 queryMonitor.queryCreatedEvent(queryInfo);
                 queryMonitor.queryCompletedEvent(queryInfo);
                 stats.queryStarted();
+                stats.queryStopped();
                 stats.queryFinished(queryInfo);
             }
             finally {
['presto-main/src/main/java/com/facebook/presto/execution/SqlQueryManager.java']