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: I2214089ed7b350c2f4d9e86131c0568164192875
Change-Id: I861a9e137e2d0938191e36f1b2d85fe5d42a0520
(cherry picked from commit fc7f390c)