Remove TunnelDirConns and PreferTunnelledDirConns

These options were added back in 0.1.2.5-alpha, but no longer make any
sense now that all directories support tunneled connections and
BEGIN_DIR cells.  These options were on by default; now they are
always-on.

This is a fix for 10849, where TunnelDirConns 0 would break hidden
services -- and that bug arrived, I think, in 0.2.0.10-alpha.
Downgrade bug 7164 warning to INFO

The 0.2.5.x warning is the one that might help us track this down; the
warnings in stable are just annoying users over and over and over.
Merge remote-tracking branch 'origin/maint-0.2.3' into maint-0.2.4

Conflicts:
	src/or/microdesc.c
Merge remote-tracking branch 'origin/maint-0.2.4'

(this is an "ours" merge, to avoid taking 6a4f5d9b4d into 0.2.5: that
commit downgrades the bug 7164 warning in versions <= 0.2.4 because it
isn't as useful as the one 0.2.5 has)
Merge remote-tracking branch 'public/bug10849_025'

Conflicts:
	src/or/config.c