use latest generic-pool (brianc#1031)

Author: Tristan Davies

package.json

@@ -19,7 +19,7 @@
   "main": "./lib",
   "dependencies": {
     "buffer-writer": "1.0.1",
-    "generic-pool": "2.1.1",
+    "generic-pool": "2.4.2",
     "packet-reader": "0.2.0",
     "pg-connection-string": "0.1.3",
     "pg-types": "1.*",