tools: check go compiler version if present

tools: check go compiler version if present

Currently, no minimum go compiler version is required by the configure
scripts. However, the go bindings actually will not build with some
older versions of go. Add a check for a minimum go version of 1.11.1 in
accordance with tools/golang/xenlight/go.mod.

Signed-off-by: Nick Rosbrook <rosbrookn@ainfosec.com>
Acked-by: George Dunlap <george.dunlap@citrix.com>
Tested-by: Nick Rosbrook <rosbrookn@ainfosec.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Release-acked-by: Paul Durrant <paul@xen.org>