runCommand was returning 'error' but checking for 'err'
resulting in an exception.
(Bitbake rev: 263aa44ed47e0cb03e1a97e7ed4a50bd9f828c78)
Signed-off-by: Martin Donnelly <martin.donnelly@ge.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>