Fix leaked memory for successive calls to SPQR
(grafted from 01def857d4f20ab36f60a4eaabc35d041add3750)

--HG--
branch : 3.2
extra : source : 01def857d4f20ab36f60a4eaabc35d041add3750
Fix SPQR Solve() when assigning to a Map object
(grafted from 705214450889f8c322e5536a3fb541e515b6cf58)

--HG--
branch : 3.2
extra : source : 705214450889f8c322e5536a3fb541e515b6cf58