Fix Tests 12,13,14,15 regex: expect show_versions()'s actual 'scriptname vX.Y' output format, not the older 'scriptname version X.Y' convention.
Found while retargeting the install-SDP fleet from dev_rebrand to dev
(2026-09-02): ccheck.sh/opt_perforce_sdp_backup.sh/configure_new_server.sh
were migrated to the shared show_versions() helper (SDP-1161/SDP-799),
which deliberately prints 'scriptname vX.Y' (confirmed consistent between
utils.lib's and libcore.sh's own show_versions() implementations) -- not
'scriptname version X.Y'. gen_p4dtg_env.sh's test entry already used the
correct 'v' pattern and passed; these four entries were never updated to
match when those three scripts were migrated, so they've been failing
(previously masked since these tests never ran clean end-to-end against
dev before now). mkdirs.sh/p4login are unmigrated and correctly keep the
'version' pattern.
Agent: Claude Code, Model: Claude Sonnet 5 (claude-sonnet-5), operating as tom_tyler.