Description: net: sit: fix memory leak in sit_init_net()
References:
Notes:
 bwh> Introduced in 4.12 by commit cf124db566e6 "net: Fix inconsistent
 bwh> teardown and release of private netdev state."  The fix was
 bwh> wrongly backported in 4.9.163, which introduced a double-free,
 bwh> then reverted in 4.9.198.
Bugs:
upstream: released (5.0) [07f12b26e21ab359261bf75cfcb424fdc7daeb6d]
4.19-upstream-stable: released (4.19.28) [d0bedaac932f4c02c080a50d4a30b2a1fec5d682]
4.9-upstream-stable: N/A "Vulnerability introduced later"
3.16-upstream-stable: N/A "Vulnerability introduced later"
sid: released (4.19.28-1)
4.19-buster-security: N/A "Fixed before branching point"
4.9-stretch-security: N/A "Vulnerability introduced later"
3.16-jessie-security: N/A "Vulnerability introduced later"