Add one metrics field to record the cause of DNS query internal error

The internal Error of DNS query have more than 100 reasons.
Record each internal error reason for us to do further analysis.

Bug: 150335075
Test: Manual test with statsd_testdrive
Merged-In: Icf24178fd38ae494ee505d38c32d6b1f3a135da3
Change-Id: I6ea9537fa3f57f143e2974843ab65e3e3afcc24e
(cherry picked from commit 507a1fd6)