[SPARK-18681][SQL] Fix filtering to compatible with partition keys of type int

## What changes were proposed in this pull request?

Cloudera put `/var/run/cloudera-scm-agent/process/15000-hive-HIVEMETASTORE/hive-site.xml` as the configuration file for the Hive Metastore Server, where `hive.metastore.try.direct.sql=false`. But Spark isn't reading this configuration file and get default value `hive.metastore.try.direct.sql=true`. As mallman said, we should use `getMetaConf` method to obtain the original configuration from Hive Metastore Server. I have tested this method few times and the return value is always consistent with Hive Metastore Server.

## How was this patch tested?

The existing tests.

Author: Yuming Wang <wgyumg@gmail.com>

Closes #16122 from wangyum/SPARK-18681.

(cherry picked from commit 90abfd15)
Signed-off-by: Herman van Hovell <hvanhovell@databricks.com>