Update candidate version to work with brew 0.9.2's info command

candidate_version relies on an awk expression that now works with brew 0.9.2

candidate_version parses the output of brew info with a regex incorporating a whitespace.

awk assumes that brew info will format output as:

tmux stable 1.6, HEAD

However, brew 0.9.2 formats as

tmux: stable 1.6, HEAD

The old awk regex couldn't pick up the 0.9.2 formatting and would always no available packages.

New awk regex is sensitive to both whitespace and colon formatted info.

sous-chefs / homebrew