Use AccountNameFlag in show account to match other commands which take an account flag.
Use AccountNameFlag in show account to match other commands which
take an account flag.

This doesn't completely obviate the previous commit as the previous
commit makes the codebase more robust against silly developers like me.

:D

BytemarkHosting/bytemark-client,BytemarkHosting/bytemark-client,BytemarkHosting/bytemark-client