qemu-iotests: strip spaces from qemu-img/qemu-io/qemu command lines A trailing space is left when qemu-img has no arguments, for example if -nocache is not used. This becomes an empty argument after split() and causes qemu-io to fail. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>