Fix tests to not make long unix domain socketpaths
Fix tests to not make long unix domain socketpaths

Some tests were running into this issue:
https://github.com/golang/go/issues/6895

Putting the sockets into temp dirs fixes the problem.

DenBeke/caddy,tw4452852/caddy,elcore/caddy,ollie314/caddy,ollie314/caddy,pyed/caddy,cez81/caddy,tobya/caddy,tw4452852/caddy,elcore/caddy,ollie314/caddy,tw4452852/caddy,joshix/caddy,DenBeke/caddy,dusty/caddy,DenBeke/caddy,ollie314/caddy,pyed/caddy,cez81/caddy,tobya/caddy,pyed/caddy,devangels/caddy,tobya/caddy,dusty/caddy,yukimochi/caddy,yukimochi/caddy,dusty/caddy,pyed/caddy,captncraig/caddy,cez81/caddy,elcore/caddy,captncraig/caddy,DenBeke/caddy,devangels/caddy,captncraig/caddy,devangels/caddy,tw4452852/caddy,dusty/caddy,tobya/caddy,joshix/caddy,joshix/caddy,yukimochi/caddy