cq: fix an error message
cq: fix an error message

The triggered_by and location_regexp configs are compatible since
https://crbug.com/1074004#c13

Bug: 1074004
Change-Id: I2e6a3613e51e2008377ab6f169d76dfc8e2e1e60
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/2732033
Auto-Submit: Michael Achenbach <76cc7f10de6bc994d83c4cb09072e4590b82b709@chromium.org>
Reviewed-by: Andrii Shyshkalov <a30c74fa30536fe7ea81ed6dec202e35e149e1fd@google.com>
Commit-Queue: Andrii Shyshkalov <a30c74fa30536fe7ea81ed6dec202e35e149e1fd@google.com>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go