hacks: build main target without go in the PATH

`make` is able to build project binaries, but fails with
error `hack/lib/golang.sh: line 455: go: command not found`
trying to place them if go binary is not in the PATH.
This happens because kube::golang::place_bins uses different
environment than kube::golang::build_binaries.

Setting up an one environment for both `kube::golang::place_bins`
and `kube::golang::build_binaries` should solve this issue and allow
default make target to fully work without go binary in the PATH.

hack/lib/golang.sh

@@ -873,10 +873,6 @@ kube::golang::get_physmem() {
 #   KUBE_BUILD_PLATFORMS - Incoming variable of targets to build for.  If unset
 #     then just the host architecture is built.
 kube::golang::build_binaries() {
-  # Create a sub-shell so that we don't pollute the outer environment
-  (
-    # Check for `go` binary and set ${GOPATH}.
-    kube::golang::setup_env
   V=2 kube::log::info "Go version: $(GOFLAGS='' go version)"
 
   local host_platform
@@ -974,5 +970,4 @@ kube::golang::build_binaries() {
       )
     done
   fi
-  )
 }

hack/make-rules/build.sh

@@ -24,5 +24,6 @@ KUBE_ROOT=$(dirname "${BASH_SOURCE[0]}")/../..
 KUBE_VERBOSE="${KUBE_VERBOSE:-1}"
 source "${KUBE_ROOT}/hack/lib/init.sh"
 
+kube::golang::setup_env
 kube::golang::build_binaries "$@"
 kube::golang::place_bins