Commit
b3ce06058c2eece633003fa37f24f304158a5280
by Oliver Smithsgsn/sgsn_vty: create state-dir
Prepare to change the state-dir in the default config in a follow-up
commit. Create the directory if it does not exist.
Change-Id: I8db4898cdaa2fcbd6bbf7c543764b9cdf828de83