Correction of usage errors.Wrap instead of errors.Wrapf

[uvyuhin]

The master build is currently failing with the following error:

Error: generator/generator.go:681:46: printf: non-constant format string in call to github.com/pkg/errors.Wrapf (govet)
	return "", errors.Wrapf(errUnknownSelector, name)
	                                            ^
make: *** [Makefile:32: lint] Error 1
Error: Process completed with exit code 2.

The method uses errors.Wrapf instead of errors.Wrap