JR45232 Request to shorten DSAttachJob minimum timeout when unable to obtain lock

The code for DSAttachJob has been modified to permit the minimum timeout to be set as low as
60 seconds. However as the previous behaviour was to ignore values of DSAttLockWait below 1800
seconds an environment variable is used to control the usage of a lower limit.

In order to have a timeout below 1800 seconds the following environment variables should be set:
DSAttLockWait  - set to the value of the required timeout.
DSAttShortWait - set to 1