Added WithNoProxy dialopts to ignore proxies for grpc connection when dealing with unix socket.

[nithu0115]

Issue #, if available: #931

Description of changes:

The non-grpc things are mostly HTTP requests that we do need to proxy. The grpc things, as noted, as via local sockets, which can't and shouldn't be proxied.

Providing our own dialer is an option, but this seems a little cleaner and like other folks might also find it useful.

== Tests ==

[ec2-user@ip-10-0-1-130 ~]$ kn describe ds/aws-node |grep -i env -A9
    Environment Variables from:
      proxy-environment-variables  ConfigMap  Optional: false
    Environment:
      AWS_VPC_K8S_CNI_LOGLEVEL:    DEBUG
      AWS_VPC_K8S_CNI_VETHPREFIX:  eni
      AWS_VPC_ENI_MTU:             9001
      MY_NODE_NAME:                 (v1:spec.nodeName)
    Mounts:
      /host/etc/cni/net.d from cni-net-dir (rw)
      /host/opt/cni/bin from cni-bin-dir (rw)
      /host/var/log from log-dir (rw)
      /var/run/docker.sock from dockersock (rw)

[ec2-user@ip-10-0-1-130 ~]$ kn exec -it aws-node-j8c5z env |grep -i proxy
HTTPS_PROXY=http://192.168.140.166:3128
HTTP_PROXY=http://192.168.140.166:3128
NO_PROXY=192.168.0.0/16,/var/run/dockershim.sock,localhost,10.100.0.0/16,127.0.0.1,169.254.169.254,.s3.us-east-2.amazonaws.com,api.ecr.us-east-2.amazonaws.com,dkr.ecr.us-east-2.amazonaws.com,ec2.us-east-2.amazonaws.com,.us-east-2.eks.amazonaws.com,.us-east-2.compute.internal

[ec2-user@ip-10-0-1-130 ~]$ kn describe cm/proxy-environment-variables
Name:         proxy-environment-variables
Namespace:    kube-system
Labels:       <none>
Annotations:
Data
====
HTTPS_PROXY:
----
http://192.168.140.166:3128
HTTP_PROXY:
----
http://192.168.140.166:3128
NO_PROXY:
----
192.168.0.0/16,/var/run/dockershim.sock,localhost,10.100.0.0/16,127.0.0.1,169.254.169.254,.s3.us-east-2.amazonaws.com,api.ecr.us-east-2.amazonaws.com,dkr.ecr.us-east-2.amazonaws.com,ec2.us-east-2.amazonaws.com,.us-east-2.eks.amazonaws.com,.us-east-2.compute.internal
Events:  <none>

[ec2-user@ip-10-0-1-130 ~]$ k get deploy
NAME         READY   UP-TO-DATE   AVAILABLE   AGE
pv-deploy    25/50   50           25          7m19s
pv-deploy6   0/100   0            0           26m

[ec2-user@ip-10-0-1-130 ~]$ kn get po -w
NAME                       READY   STATUS    RESTARTS   AGE
aws-node-j8c5z             1/1     Running   0          20m
aws-node-ss4vp             1/1     Running   0          22m
coredns-74dd858ddc-jw2bm   1/1     Running   0          16h
coredns-74dd858ddc-zcxdd   1/1     Running   0          16h
kube-proxy-pm46g           1/1     Running   0          13h
kube-proxy-xfhbw           1/1     Running   0          13h

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[nithu0115]

Waiting to complete my E2E tests.

[haouc]

Looks good to me.

[nithu0115]

Attached tests to PR. Let me know if you have any questions.

[mogren]

Nice, great fix!

[rimaulana]

Tested this patch and it works in my env