Bug 1536154

Description of problem:
go get functionality broken in devtools golang container on registry.access.redhat.com/devtools/go-toolset-7-rhel7

When a `go get` command is invoked, Go is unable to get packages for our application sources from Github/Gitlab/Bitbucket/Bazaar because the revision control system executables are not present.

bash-4.2$ go get github.com/golang/example/hello
go: missing Git command. See https://golang.org/s/gogetcmd
package github.com/golang/example/hello: exec: "git": executable file not found in $PATH

Version-Release number of selected component (if applicable):
Red Hat Developer Toolset 7.0
registry.access.redhat.com/devtools/go-toolset-7-rhel7:latest

How reproducible:
Always

Steps to Reproduce:
1. Download/Install from Git and Bazaar revision control systems into the Docker image.
2. $ go get github.com/golang/example/hello


Actual results:
# docker exec -it go-toolset-7 bash

bash-4.2$ export GOPATH=/opt/app-root 
bash-4.2$ go get github.com/golang/example/hello
go: missing Git command. See https://golang.org/s/gogetcmd
package github.com/golang/example/hello: exec: "git": executable file not found in $PATH
bash-4.2$ which git
which: no git in (/opt/rh/go-toolset-7/root/usr/bin:/opt/rh/go-toolset-7/root/usr/sbin:/opt/app-root/src/bin:/opt/app-root/bin:/opt/rh/go-toolset-7/root/usr/bin/:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin)
bash-4.2$ rpm -qa | grep -i git
bash-4.2$ 


Expected results:
Should be able to get sources from git repos.

Additional info: