Currently the proxy's TLS fallback if an NLA connection attempt failed
is broken. There are two issues with the current code that this PR
fixes:
- freerdp_reconnect is used which requires an already established
connection to work correctly. This is not the case since the NLA
connectin attempt failed. This resulted in a seemingly working TLS
connection but i.e. channels where missing/not working.
- The fallback connection attempt just altered the NLA security setting
in the instance's settings. However these settings have been already
modified by the NLA connection attempt so we need to create a copy of
the original connection settings before doing the first connect.
The PR also introduces freerdp_reset_context which restores the initial
connection settings for the given instance.
4b9fb8fff9