Incompatibility with autocomplpop / does not handle pumvisible()

[blueyed]

A visible popup menu will cause <cr> to do (effectively) nothing, instead of accepting the selected element.

To reproduce:

1. Install autocomplpop
2. vim test.sh
3. enter this text:

   !/bin/ba

4. A popup will appear suggesting /bin/bash, but selecting it won't do anything.

This does not happen in general, but I have noticed it in the corner case mentioned above only. This might be related to the shell-filetype only.

[chanil1218]

Same here