vpn-manager: Create /mnt/stateful_partition/etc if it does not exist.

IpsecManager originally assumed that /mnt/stateful_partition/etc already
exists when it tries to create files such as ipsec.conf in that
directory. That is no longer true. To avoid making such an assumption,
this CL changes IpsecManager to create /mnt/stateful_partition/etc if it
does not exist.

BUG=chromium-os:29485
TEST=Tested the following:
1. Build vpn-manager for {x86,amd64,arm}-generic.
2. Run vpn-manager unit tests.
3. Manually remove /mnt/stateful_partition/etc on a Cr48 and verify that
   l2tpipsec_vpn creates that directory when starting a VPN connection.

Change-Id: Ie01ba321f0dee97e0aac102aa7546227213bf292
Reviewed-on: https://gerrit.chromium.org/gerrit/20292
Reviewed-by: Paul Stewart <pstew@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
Commit-Ready: Ben Chan <benchan@chromium.org>
1 file changed