Add go "dep" tool to support lockfiles in go pkgs

The go compiler supports "go get" to download dependencies, but
it will download the latest version of dependencies from the git
repository of the dependency.  This could lead to non-reproducable
builds, or the potential of dependency API changes (including
deprecated features) to break the build of packages.

The "dep" tool allows for a lockfile to be created, which captures
the git commit ID of dependencies, and can restore dependencies to
the captured state.

Since no binary package containing "dep" is currently available for
CentOS, this change adds the package and compiles it from source.

Depends-On: https://review.openstack.org/625333

Story: 2004617
Task: 28525

Change-Id: Ic3bfad6a419b344e7c147c3839d16956c432a99e
Signed-off-by: Jason McKenna <jason.mckenna@windriver.com>

tools/golang-dep/centos/build_srpm.data

@@ -0,0 +1,2 @@
+COPY_LIST="$CGCS_BASE/downloads/dep-v0.5.0.tar.gz"
+TIS_PATCH_VER=0

tools/golang-dep/centos/golang-dep.spec

@@ -0,0 +1,45 @@
+Name:           golang-dep
+Version:        0.5.0
+Release:        %{tis_patch_ver}%{?_tis_dist}
+Summary:        Go dep dependency management tool
+Group:          Development/Languages
+License:        Go
+URL:            https://github.com/golang/dep
+Source:         dep-v0.5.0.tar.gz
+BuildRequires:  golang
+Requires:       golang
+
+%global with_debug 0
+%global debug_package %{nil}
+%define __spec_install_post %{nil}
+
+%define tooldir %{_libdir}/go/pkg/%{name}/linux_amd64
+
+%if ! 0%{?gobuild:1}
+%define gobuild(o:) go build -ldflags "${LDFLAGS:-} -B 0x$(head -c20 /dev/urandom|od -An -tx1|tr -d ' \\n')" -a -v -x %{?**};
+%endif
+
+%description
+This package includes additional go development tools.
+
+%prep
+%setup -T -c -n go/src/github.com/golang/dep
+tar --strip-components=1 -x -f %{SOURCE0}
+
+%build
+export GOPATH=%{_builddir}/go
+(cd cmd/dep && %gobuild -o dep)
+
+%install
+rm -rf %{buildroot}
+install -d %{buildroot}%{_bindir}
+install -d %{buildroot}%{tooldir}
+install cmd/dep/dep %{buildroot}%{_bindir}
+
+%clean
+rm -rf %{buildroot}
+
+%files
+%defattr(-,root,root,-)
+%{_bindir}/dep
+