ipvs: change some data types from int to bool

Change the data type of the following variables from int to bool
across ipvs code:

  - found
  - loop
  - need_full_dest
  - need_full_svc
  - payload_csum

Also change the following functions to use bool full_entry param
instead of int:

  - ip_vs_genl_parse_dest()
  - ip_vs_genl_parse_service()

This patch does not change any functionality but makes the source
code slightly easier to read.

Signed-off-by: Andrea Claudi <aclaudi@redhat.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>