Restore parsing of gentoo string with condition (#195)

* cmd/helpers: Permit to parse gentoo package str with condition

* Update vendor pkgs-checker @v0.8.1

vendor/github.com/hashicorp/go-version/.travis.yml

@@ -1,13 +0,0 @@
-language: go 
-
-go: 
-  - 1.2
-  - 1.3
-  - 1.4
-  - 1.9
-  - "1.10"
-  - 1.11
-  - 1.12
-  
-script:
-  - go test 

vendor/github.com/hashicorp/go-version/README.md

@@ -1,5 +1,6 @@
 # Versioning Library for Go
-[![Build Status](https://travis-ci.org/hashicorp/go-version.svg?branch=master)](https://travis-ci.org/hashicorp/go-version)
+[![Build Status](https://circleci.com/gh/hashicorp/go-version/tree/master.svg?style=svg)](https://circleci.com/gh/hashicorp/go-version/tree/master)
+[![GoDoc](https://godoc.org/github.com/hashicorp/go-version?status.svg)](https://godoc.org/github.com/hashicorp/go-version)
 
 go-version is a library for parsing versions and version constraints,
 and verifying versions against a set of constraints. go-version

vendor/github.com/hashicorp/go-version/version.go

@@ -280,6 +280,10 @@ func comparePrereleases(v string, other string) int {
 
 // Equal tests if two versions are equal.
 func (v *Version) Equal(o *Version) bool {
+	if v == nil || o == nil {
+		return v == o
+	}
+
 	return v.Compare(o) == 0
 }
 
@@ -288,7 +292,7 @@ func (v *Version) GreaterThan(o *Version) bool {
 	return v.Compare(o) > 0
 }
 
-// GreaterThanOrEqualTo tests if this version is greater than or equal to another version.
+// GreaterThanOrEqual tests if this version is greater than or equal to another version.
 func (v *Version) GreaterThanOrEqual(o *Version) bool {
 	return v.Compare(o) >= 0
 }
@@ -298,7 +302,7 @@ func (v *Version) LessThan(o *Version) bool {
 	return v.Compare(o) < 0
 }
 
-// LessThanOrEqualTo tests if this version is less than or equal to another version.
+// LessThanOrEqual tests if this version is less than or equal to another version.
 func (v *Version) LessThanOrEqual(o *Version) bool {
 	return v.Compare(o) <= 0
 }