REGTEST/MINOR: Wrong URI syntax.

Ilya Shipitsin reported that with some curl versions this reg test
may fail due to a wrong URI syntax with ::1 ipv6 local address in
this varnishtest script. This patch fixes this syntax issue and
replaces the iteration of "procees" commands by a "shell" command
to start curl processes (must be faster).

Thanks to Ilya Shipitsin for having reported this VTC file bug.
1 file changed