Update to new upstream release candidate 2.74rc1.

To fix three regressions in 2.73:

1. The meaning of --conf-file without an argument changed from "don't

read any conf-file" to "read the default conf-file"

2. A resolv-file which was dangling symlink at startup causes

problems, up to and including a segmentation fault.

3. Under some circumstances, dnsmasq can use more file descriptors,

and this shows up that the code doesn't handle the limit (normally

1024. in the number of descriptors handled by the select() system call.