HPCC-12297 assert(hostname) error if SOAPCALL to invalid IP

Currently CSocket::pre_connect asserts that the hostname is valid. This
pull request changes the assertex to a JSocket exception with a meaningful

Signed-off-by: William Whitehead <william.whitehead@lexisnexis.com>
Merge pull request #6463 from RussWhitehead/assertex

HPCC-12297 assert(hostname) error if SOAPCALL to invalid IP

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>