mariadb: Add mysql5 to RPROVIDES for backwards compatibility

It failed to build image while IMAGE_INSTALL += "mysql5"
For backwards compatibility:
- Add mysql5 to RPROVIDES_${PN}
- Add mysql5-dbg to RPROVIDES_${PN}-dbg
- Add mysql5-leftovers to RPROVIDES_${PN}-leftovers
- Use "+=" instead of "=" in  RPROVIDES_${PN}-client and
  RPROVIDES_${PN}-server

The same to RREPLACES and RCONFLICTS.

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>