bug#37464: 26.3; Icomplete and TRAMP create unnecessary buffer

[Andrii Kolomoiets]

1. emacs -Q
2. M-x icomplete-mode
3. C-x C-f
4. /q::
   instead of "q" allowed method can be specified e.g. "sudo" or "ssh"
5. C-g
6. C-x C-b

Notice new buffer "*tramp/q..." created although command was cancelled.

In GNU Emacs 26.3 (build 1, x86_64-apple-darwin18.2.0, NS appkit-1671.20 
Version 10.14.3 (Build 18D109))
of 2019-09-02 built on builder10-14.porkrind.org