Advance-toolchain 10.0 for MariaDB-10.2

advance-toolchain-10.0 got released today. Its based on gcc-6.2.1. I'd like to think there are advances in the compiler.

Getting mariadb-10.2 packages built with this version would be a good time since its still pre-release.

The yum packages for development and runtime AT8.0 and AT10.0 are installable at the same time without conflicts for the builders (RHEL/Centos7). This will be important if galera compiled against a different version.

I've compiled the latest 10.2 code, debug and release against at10.0 and there are no compile or mtr (big-test included) problems. There are a couple of compiler warnings however nothing too significant.