[source/native] fix sqlserver pattern matcher for unique constraints (closes #3227593) The matcher is used to parse the low-level error message and extract meaningful information for the end users. If broken, the users see an alarming and bewildering message. A full & definitive fix is scheduled for CubicWeb 3.18.

\.svn
^build$
^dist$
\.pyc$
\.pyo$
\.bak$
\.old$
\~$
\#.*?\#$
\.swp$
^doc/book/en/apidoc$
\.old$
syntax: regexp
.*/data/database/.*\.sqlite
.*/data/database/.*\.config
.*/data/database/tmpdb.*
.*/data/ldapdb/.*
^doc/html/
^doc/doctrees/
^doc/book/en/devweb/js_api/