Stop checking threshold validity
Stop checking threshold validity

This has moved to the client config. Also the check as stated didn't
make sense -- it was always supposed to be valid to specify only some
of the thresholds, while omitting others (resulting in a default value
of 0).

Pre-push hook installed.

Change-Id: Ibb109967813829da2738875b205542e5e9d63bb7

googleapis/gapic-generator,googleapis/gapic-generator,swcloud/toolkit,googleapis/gapic-generator,swcloud/toolkit,shinfan/toolkit,jcanizales/toolkit,jmuk/toolkit,swcloud/toolkit,shinfan/toolkit,tcoffee-google/toolkit,swcloud/toolkit,swcloud/toolkit,googleapis/gapic-generator,googleapis/gapic-generator,jcanizales/toolkit,googleapis/gapic-generator,saicheems/toolkit,saicheems/toolkit,shinfan/toolkit,shinfan/toolkit,shinfan/toolkit,geigerj/toolkit,googleapis/gapic-generator