Fix build failure when compiling IntAna_Curve.cxx

This bug had been introduced when upgrading OCCT-patches
to OCCT 6.7.0.  We patched src/IntAna/IntAna_Curve.cxx
in c35fc63 to get rid of compiler warnings.
A different fix has been applied in OCCT 6.7.0, the
final return has been dropped, so our change has to
be removed from
  patches/submitted/thread_21388/warning/fix-uninitialized-var.patch