Canceling a completion operation deletes the frame

[wongandj]

I have discovered that canceling a completion with frames-only-mode enabled causes the whole frame to be deleted.

To reproduce:

1. Start emacs -q.
2. Type C-x 5 b RET to open the scratch buffer in another window.
3. Type string or other complete-able phrase.
4. Type C-M-i, then C-g. Observe how the frame isn't killed.
5. Type M-x frames-only-mode.
6. Attempt step 4, and watch the frame get killed.