functions: fix unhelpful error for binary not found on PATH
with the config:
BINARIES=(nonexistant /usr/bin/nonexistant)
before:
==> ERROR: file not found: ''
==> ERROR: file not found: '/usr/bin/nonexistant'
after:
==> ERROR: binary not found: 'nonexistant'
==> ERROR: file not found: '/usr/bin/nonexistant'
Edited by classabbyamp