HPCC-9882 Check and return exception message from removeEntry()

This fix is based on the fix in pull request 4968 which allows the
removeEntry() to send out exception message to caller. This fix sets
the throwException flag to true when WsDFU calls the removeEntry(). If
an exception is catched, the existing code will sent the exception
message to EclWatch to display.
HPCC-9882 Do not check the return from removeEntry()
Merge pull request #4972 from wangkx/h9882

HPCC-9882 Check and return exception message from removeEntry()

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>