Skip auto-transport when transport available

[mrpalide]

Did you run make format && make check? Yes

Fixes #1297

Changes:

• add a condition at the beginning of getRouteSetupHooks method (a.k.a. autotransport) to skip whole of process if a transport from visor to vpn-server be available.

How to test this PR:

• make build
• run a visor (in debug log-level), and run a vpn-server (you can use 036c0e89735c675abce702a3d46ad1bf736bd8236dbd734bfaf368959de2c2b967)
• create manual transport in dmsg or sudph to vpn-server
• trying to run vpn-client
• should see this log on visor logs Debug [router]: Established transport exist. Type: dmsg, and no trying for new transport in order stcpr>sudph>dmsg
• also vpn-client should running on exist transport, so check Routing tab of visor details