BUG/MEDIUM: resolve: fix init resolving for ring and peers section.

BUG/MEDIUM: resolve: fix init resolving for ring and peers section.

Reported github issue #759 shows there is no name resolving
on server lines for ring and peers sections.

This patch introduce the resolving for those lines.

This patch adds  boolean a parameter to parse_server function to specify
if we want the function to perform an initial name resolving using libc.

This boolean is forced to true in case of peers or ring section.

The boolean is kept to false in case of classic servers (from
backend/listen)

This patch should be backported in branches where peers sections
support 'server' lines.