This PR allows 'minio update' to not only shows update banner
but also allows for in-place upgrades.
Updates are done safely by validating the downloaded
sha256 of the binary.
Fixes#4781
- over the course of a project history every maintainer needs to update
its dependency packages, the problem essentially with godep is manipulating
GOPATH - this manipulation leads to static objects created at different locations
which end up conflicting with the overall functionality of golang.
This also leads to broken builds. There is no easier way out of this other than
asking developers to do 'godep restore' all the time. Which perhaps as a practice
doesn't sound like a clean solution. On the other hand 'godep restore' has its own
set of problems.
- govendor is a right tool but a stop gap tool until we wait for golangs official
1.5 version which fixes this vendoring issue once and for all.
- govendor provides consistency in terms of how import paths should be handled unlike
manipulation GOPATH.
This has advantages
- no more compiled objects being referenced in GOPATH and build time GOPATH
manging which leads to conflicts.
- proper import paths referencing the exact package a project is dependent on.
govendor is simple and provides the minimal necessary tooling to achieve this.
For now this is the right solution.