Allow spaces in the SSH ControlPath

[blackwood821]

This addresses #240

[bahamat]

This looks good, but we'd like to see some testing cases with example output.

[blackwood821]

@bahamat Here is what we were getting before my change:

C:\Users\Test User>triton ssh sandbox
command-line line 0: garbage at end of line; "User\\AppData\\Roaming\\Joyent\\Triton\\tmp\\nullSshControlPath"

And here is what we got after my change:

C:\Users\Test User>triton ssh sandbox
Warning: Permanently added '10.10.50.105' (ED25519) to the list of known hosts.

  ,---.                   |     ,---. ,---.
  `---. ,-.-. ,---. ,---. |---  |   | `---.  base-64-lts
      | | | | ,---| |     |     |   |     |  22.4.0
  `---' ` ' ' `---' `     `---' `---' `---'

[root@sandbox ~]#