Add --location CLI opt to refinery-drop-webrequest-partitions

Since data location in external tables is defined by partition, not
by table schema, and since we recently removed the base table
location information from the webrequest table schema, this
script needs to know where to look for webrequest data in HDFS.

Change-Id: Icfd327195569ef8f1eba12ea50ba6c0dba4fb5e3
Merge "Add --location CLI opt to refinery-drop-webrequest-partitions"