bugfix: fix the wrong bridge gateway

[rudyfly]

Ⅰ. Describe what this PR did

Before default nat network is 172.17.0.1/24, commit: 7e7f607 has
changed it to 192.168.5.1/24. If "p0" is exist, pouchd start will check
gateway is error.

Ⅱ. Does this pull request fix one issue?

fixes #1494

Ⅲ. Describe how you did it

When get the bridge route is nil and haven't configed gateway in config.json, so we use bridge ip address as gateway.

Ⅳ. Describe how to verify it

set p0 bridge as before 172.17.0.1/24, and start pouchd

Ⅴ. Special notes for reviews

Signed-off-by: Rudy Zhang [email protected]

[codecov-io]

Codecov Report

Merging #1495 into master will decrease coverage by 0.08%.
The diff coverage is 68.18%.

@@            Coverage Diff             @@
##           master    #1495      +/-   ##
==========================================
- Coverage   40.45%   40.37%   -0.09%     
==========================================
  Files         253      251       -2     
  Lines       16466    16475       +9     
==========================================
- Hits         6662     6651      -11     
- Misses       8948     8969      +21     
+ Partials      856      855       -1

Impacted Files	Coverage Δ
network/mode/bridge/bridge.go	60.36% <68.18%> (+3.49%)	⬆️
client/network_connect.go	0% <0%> (-100%)	⬇️
client/container_exec.go	0% <0%> (-80%)	⬇️
client/container_attach.go
client/container_upgrade.go
client/container_logs.go
client/container.go	0% <0%> (ø)
ctrd/container.go	50.18% <0%> (+0.72%)	⬆️
daemon/logger/jsonfile/utils.go	71.66% <0%> (+1.66%)	⬆️
ctrd/image.go	79.42% <0%> (+2.85%)	⬆️

[Letty5411]

LGTM