Romain Vimont authored Nov 10, 2017 and Jean-Baptiste Kempf committed Nov 11, 2017

The macro qtu() is defined as follows:

    #define qtu( i ) ((i).toUtf8().constData())

"i" is a QString, .toUtf8() returns a QByteArray, .constData() returns a
pointer to the data inside the QByteArray.

It is important to notice that the QByteArray is temporary. Therefore,
it is "destroyed as the last step in evaluating the full-expression that
(lexically) contains the point where [it was] created".

Concretely, this means that this call is correct:

    do_something( qtu( string ) );

But this one is undefined behavior:

    const char *s = qtu( string );
    do_something( s );

Thus, here, bookmark.psz_name was initialized with a pointer to garbage
data.

To fix the problem, store the QByteArray in a local variable so that it
lives long enough.

(Fixes invalid reads reported by valgrind)

Signed-off-by: Romain Vimont <rom@rom1v.com>
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>