The value returned by rdline_init() was not checked in cmdline_new().
On error, free the allocated memory and return NULL.
This condition should not happen today, but it's safer to do the check
in case rdline_init() is updated.
Coverity issue: 13204
Fixes: af75078fece3 ("first public release")
Signed-off-by: Marcin Kerlin <marcinx.kerlin@intel.com>
Signed-off-by: Olivier Matz <olivier.matz@6wind.com>