git get leaves behind empty folders if it fails

[wallrj]

I ran ./get github.com/grdl/git-get which failed because I forgot the https://, but it left behind a bunch of empty folders.

richard   master  …  github.com  grdl  git-get  ./get github.com/grdl/git-get
Cloning into '/home/richard/repositories/github.com/github.com/grdl/git-get'...
remote: Not Found
fatal: repository 'https://github.com/github.com/grdl/git-get/' not found
Error: "git clone https://github.com/github.com/grdl/git-get /home/richard/repositories/github.com/github.com/grdl/git-get": exit status 128


 richard   master  …  github.com  grdl  git-get  tree ~/repositories
/home/richard/repositories
└── github.com
    └── github.com
        └── grdl

3 directories, 0 files

I think it'd be nice to delete those if the command fails.
Maybe it could `git clone ... target/directory.tmpXXXX and then rename that after the command succeeds and delete it if the command fails.

[grdl]

Fixed in v0.3.0.