provider/maas: report arch matching tools in tests

The architecture of the instances must match the
architecture of the tools uploaded, which is the
same as version.Current.Arch in the tests.

__fixes-1358768__
Merge pull request #552 from axw/lp1358768-provider-maas-i386

provider/maas: report arch matching tools in tests

The architecture of the instances must match the
architecture of the tools uploaded, which is the
same as version.Current.Arch in the tests.

__fixes-1358768__