enable gocritic linter

The linter ensures a common code style.
- use switch/case instead of else if
- use if instead of switch/case for single case statement
- add space between comment and text
- detect the use of defer with os.Exit()
- use short form var += "..." instead of var = var + "..."
- detect problems with append()
```
newSlice := append(orgSlice, val)
```
  This could lead to nasty bugs because the orgSlice will be changed in
  place if it has enough capacity too hold the new elements. Thus we
  newSlice might not be a copy.

Of course most of the changes are just cosmetic and do not cause any
logic errors but I think it is a good idea to enforce a common style.
This should help maintainability.

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/libpod/networking_slirp4netns.go b/libpod/networking_slirp4netns.go
index 4a0ef0b3a..788834435 100644
--- a/libpod/networking_slirp4netns.go
+++ b/libpod/networking_slirp4netns.go
@@ -82,7 +82,9 @@ func checkSlirpFlags(path string) (*slirpFeatures, error) {
 }
 
 func parseSlirp4netnsNetworkOptions(r *Runtime, extraOptions []string) (*slirp4netnsNetworkOptions, error) {
-	slirpOptions := append(r.config.Engine.NetworkCmdOptions, extraOptions...)
+	slirpOptions := make([]string, 0, len(r.config.Engine.NetworkCmdOptions)+len(extraOptions))
+	slirpOptions = append(slirpOptions, r.config.Engine.NetworkCmdOptions...)
+	slirpOptions = append(slirpOptions, extraOptions...)
 	slirp4netnsOpts := &slirp4netnsNetworkOptions{
 		// overwrite defaults
 		disableHostLoopback: true,