Automatic merge from submit-queue (batch tested with PRs 42659, 43370)
dockershim: process protocol correctly for port mapping
**What this PR does / why we need it**:
dockershim: process protocol correctly for port mapping.
**Which issue this PR fixes**
Fixes#43365.
**Special notes for your reviewer**:
Should be included in v1.6.
**Release note**:
```release-note
NONE
```
cc/ @Random-Liu @justinsb @kubernetes/sig-node-pr-reviews