Correcting all go vet errors

pkg/labels/selector.go

@@ -466,7 +466,6 @@ func (p *Parser) parse() ([]Requirement, error) {
 			return nil, fmt.Errorf("found '%s', expected: identifier or 'end of string'", lit)
 		}
 	}
-	return requirements, nil
 }
 
 func (p *Parser) parseRequirement() (*Requirement, error) {
@@ -558,7 +557,6 @@ func (p *Parser) parseValues() (util.StringSet, error) {
 	default:
 		return nil, fmt.Errorf("found '%s', expected: ',', ')' or identifier", lit)
 	}
-	return util.NewStringSet(), nil
 }
 
 // parseIdentifiersList parses a (possibly empty) list of