jquery_colorpicker_requirements() does not return a value; install profiles that include jquery_colorpicker fail

I am including jQuery Colorpicker in an install profile. It was failing with:

Unsupported operand types in includes/install.core.inc on line 721

A bit of debugging nailed it down to jquery_colorpicker module. I found these related issues:

http://drupal.org/node/1314616
http://drupal.org/node/1158926

The root cause is that install_check_requirements() expects that each implemention of hook_requirements() returns an array. If an implementation doesn't, then you get the error above.

Attached is a patch that fixes the issue.