CI: Ensure downloaded version of golang used

The script used to install golang was downloading and installing the
binary package, but not actually using the new golang version.

Signed-off-by: James O. D. Hunt <james.o.hunt@intel.com>

.ci/install_go.sh

@@ -109,3 +109,13 @@ info "Install go"
 mkdir -p "${install_dest}"
 sudo tar -C "${install_dest}" -xzf "${archive}"
 popd
+
+# Make sure we use the golang version we just installed
+goroot="${install_dest}/go"
+
+[ -d "${goroot}" ] || die "failed to find expected golang path ${goroot} (from ${archive})"
+
+export GOROOT="${goroot}"
+export PATH="$GOROOT/bin:$PATH"
+
+info "Using golang binary $(command -v go) version $(go version)"