Unit Test - errorhandlers.go

Add unit tests to validate methods under utils package which are defined in [errorhandlers.go](https://github.com/apache/incubator-openwhisk-wskdeploy/blob/master/utils/errorhandlers.go)

All unit tests should go in errorhandlers_test.go under utils/

```
// panic when there is an error
func Check(e error) {
...
}
```

Start with utils/errorhandlers.go, focusing on the methods under the utils package such as Check, which panics when given an error. Add the unit tests to utils/errorhandlers_test.go and run the utils package tests. Done means the relevant error-handler methods have test coverage for their stated behavior.

Written by the indexing model from the issue text.