Revert "Revert "don't enlist sql command cache dependencies""

This reverts commit 937ea5eec97cf5033110e8e5e2e8c68c43936ef2.

Revert "don't enlist sql command cache dependencies"

This reverts
commit ae9395c4670318847187314d384b1a0c28e07571.

don't enlist sql command cache dependencies

if not compatible (no
mssql), simply don't enlist the cache dependencies
and issue a warning
instead of crashing. If you have a <region/> in your
Web.config but your
connection string is resolved dynamically (for one
client using mssql
and for one client for instance mysql) - you'd have
to alter the web
config everytime, which is not good...