test/inputrc: do not set print-completions-horizontally

It interferes with completion-display-width 0 on bash 4.2, and is
unnecessary now anyway.

Author: scop

test/config/inputrc

@@ -10,9 +10,6 @@ set bell-style none
 # Don't query user about viewing the number of possible completions
 set completion-query-items -1
 
-# Display completions sorted horizontally, not vertically
-set print-completions-horizontally on
-
 # Don't use pager when showing completions
 set page-completions off