Added support for other names than vboxmanage.

Currently the completion script will be available for commands:
VBoxManage and vboxmanage. With this commit, renaming/linking this
script with another name will also make that name to be included to
completion.

For example, with alias:

    $ alias vb="VBoxManage"

linkig completion script into new name an source it:

    $ cd /path/of/completion/script/
    $ ln -s VBoxManage vb
    # source vb

will start to complete vb command.

VBoxManage

@@ -2864,4 +2864,9 @@ _VBoxManage() {
 complete -o default -F _VBoxManage VBoxManage
 complete -o default -F _VBoxManage vboxmanage
 
+if [[ "${BASH_SOURCE[0]}" != 'VBoxManage' &&
+    "${BASH_SOURCE[0]}" != 'vboxmanage' ]]; then
+    complete -o default -F _VBoxManage $(basename "${BASH_SOURCE[0]}")
+fi
+
 # vim: set ft=sh tw=80 sw=4 et :