fix(client):Adjust indentation in keys_add function

While running deis keys:add , if there are no keys the client is printing No SSH public keys found and throwing an error .
Adjusted the indendation , So if client dont find the public keys prints No SSH public keys and prints usage deis keys:add [<keys>]
Merge branch 'smothiki-keys-add-fix' of github.com:smothiki/deis into smothiki-keys-add-fix