freeradius2: remove weird circular dependencies

Signed-off-by: Etienne CHAMPETIER <champetier.etienne@gmail.com>
freeradius2: enable freeradius2-mod-sql-mysql again

compile tested only

Signed-off-by: Etienne CHAMPETIER <champetier.etienne@gmail.com>
Merge pull request #169 from champtar/freeradius2

freeradius2: remove weird circular dependencies, enable mysql again