autocomplete.channelfinder: fixing the condition to stop searching once limit is reached

Signed-off-by: Kunal Shroff <shroffk@bnl.gov>
Merge branch '3.2.x' of ssh://git@github.com/ControlSystemStudio/cs-studio.git into 3.2.x
Merge branch '3.2.x' of ssh://git@github.com/ControlSystemStudio/cs-studio.git into 3.2.x