Use -g instead of --filename-pattern as Ag argument
Use -g instead of --filename-pattern as Ag argument

This change undoes one of the two changes made in #564 so resolve an
issue for non macOS environments with Ag and ctrlp.

tchiarato/dotfiles,bschmoker/dotfiles,koerbcm/dotfiles,astoellis/dotfiles,YepengFan/dotfiles,YepengFan/dotfiles,koerbcm/dotfiles,koerbcm/dotfiles,tchiarato/dotfiles,koerbcm/dotfiles,moofish32/dotfiles,astoellis/dotfiles,bschmoker/dotfiles,toobulkeh/dotfiles,koerbcm/dotfiles,ren/dotfiles,ren/dotfiles,moofish32/dotfiles