chapel: Fix for Linuxbrew
chapel: Fix for Linuxbrew

See https://gist.github.com/04fb73154746b7e279d5

Message:
> Warning: tried to install empty array to /home/bob/.linuxbrew/Cellar/chapel/1.12.0/bin

Closes Linuxbrew/linuxbrew#876.
Closes Linuxbrew/linuxbrew#877.

Signed-off-by: Shaun Jackman <b580dab3251a9622aba3803114310c23fdb42900@gmail.com>

DoomHammer/linuxbrew,Linuxbrew/linuxbrew,Angeldude/linuxbrew,Homebrew/linuxbrew,SuperNEMO-DBD/cadfaelbrew,Linuxbrew/linuxbrew,sjackman/linuxbrew,Linuxbrew/linuxbrew,Angeldude/linuxbrew,Homebrew/linuxbrew,reelsense/linuxbrew,gnubila-france/linuxbrew,DoomHammer/linuxbrew,gnubila-france/linuxbrew,SuperNEMO-DBD/cadfaelbrew,DoomHammer/linuxbrew,sjackman/linuxbrew,Homebrew/linuxbrew,drbenmorgan/linuxbrew,SuperNEMO-DBD/cadfaelbrew,sjackman/linuxbrew,DoomHammer/linuxbrew,Angeldude/linuxbrew,saketkc/linuxbrew,drbenmorgan/linuxbrew,reelsense/linuxbrew,drbenmorgan/linuxbrew,saketkc/linuxbrew,reelsense/linuxbrew,Angeldude/linuxbrew,SuperNEMO-DBD/cadfaelbrew,reelsense/linuxbrew,Linuxbrew/linuxbrew,saketkc/linuxbrew,Homebrew/linuxbrew,gnubila-france/linuxbrew,sjackman/linuxbrew,drbenmorgan/linuxbrew,gnubila-france/linuxbrew,saketkc/linuxbrew