gboolean is a typedef for "int".

While older compilers might treat such bitfields as unsigned ([1]),
commonly such a bitfield is signed and can only contain the values 0
and -1.

We only want to use numeric 1 for TRUE, hence, creating such bitfields
is wrong, or at least error prone.

In fact, in this case it's a bug, because later we compare
it with a regular gboolean

  if (priv->scanning != new_scanning)

[1] https://lgtm.com/rules/1506024027114/

Fixes: e0f96770