This fix tries to address the issue raised in 25855 where the command
`docker deploy` can only accept a STACK without extension of `.dab`.
In other words, `docker deploy hellojavaee.dab` gives an error:
```
Bundle hellojavaee.dab.dab not found. Specify the path with --file
```
This fix updates the way namespace STACK is taken so that in case
`STACK.dab` is provided with `docker deploy`:
```
$ docker deploy STACK.dab
```
The `STACK` is used as namespace (instead of `STACK.dab`).
NOTE: This fix will only allows `.dab` extension in namespace, because
it is not possible to have a namespace with `.` in the middle. In other
words, a namespace `hello.java.ee` will not work anyway (whether the file
`hello.java.ee` exists or not).
An additional integration test has been added to cover the changes.
This fix fixes 25855.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
1e9d04c458