buildroot

core/pkg-download: fix autobuilder fallout

Some arguments can be empty, so we need to add single quote around them
But since they are sinple quote; double quote inside them are now not
interpreted by the shell and as such must be removed; hence the use of
qstrip.

Signed-off-by: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>