Decrease tempest BUILD_TIMEOUT

The BUILD_TIMEOUT is the generally used timeout option in tempest.

Almost never expected to any operation takes more than 60 sec,
the 400 sec is too match for timeout.
Changing the BUILD_TIMEOUT to 196 sec, it is still expected to be safe.

It can make faster the failing test jobs.

Change-Id: I7e7c767400ca448cb86d27b60a1229a2afa69726
Merge "Decrease tempest BUILD_TIMEOUT"