Updated some typo in istio installatio readme. (#960)
Updated some typo in istio installatio readme. (#960)

Automatic merge from submit-queue

Updated some typo in istio installatio readme.

**Release note**:

```release-note
None
```
This is a follow up PR for https://github.com/istio/istio/pull/945#discussion_r141237219

/cc @andraxylia
sebrandon1/istio,sebrandon1/istio,sebrandon1/istio,sebrandon1/istio