net/mac80211/mesh.c: correct the argument to __mesh_table_free

In the function mesh_table_grow, it is the new table not the argument table
that should be freed if the function fails (cf commit
bd9b448f

)

The semantic match that detects this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@r exists@
local idexpression x;
expression E,f;
position p1,p2,p3;
identifier l;
statement S;
@@

x = mesh_table_alloc@p1(...)
...
if (x == NULL) S
... when != E = x
    when != mesh_table_free(x)
goto@p2 l;
... when != E = x
    when != f(...,x,...)
    when any
(
return \(0\|x\);
|
return@p3 ...;
)

@script:python@
p1 << r.p1;
p2 << r.p2;
p3 << r.p3;
@@

print "%s: call on line %s not freed or saved before return on line %s via line %s" % (p1[0].file,p1[0].line,p3[0].line,p2[0].line)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>