Fixes #866 mark commit state dirty when Connection.getMetaData() is called.

src/main/java/com/zaxxer/hikari/pool/ProxyConnection.java

@@ -22,6 +22,7 @@ import java.lang.reflect.InvocationHandler;
 import java.lang.reflect.Proxy;
 import java.sql.CallableStatement;
 import java.sql.Connection;
+import java.sql.DatabaseMetaData;
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
 import java.sql.Savepoint;
@@ -346,6 +347,14 @@ public abstract class ProxyConnection implements Connection
       return ProxyFactory.getProxyPreparedStatement(this, trackStatement(delegate.prepareStatement(sql, columnNames)));
    }
 
+   /** {@inheritDoc} */
+   @Override
+   public DatabaseMetaData getMetaData() throws SQLException
+   {
+      markCommitStateDirty();
+      return delegate.getMetaData();
+   }
+
    /** {@inheritDoc} */
    @Override
    public void commit() throws SQLException