Misc edits: makefiles/ and jjb templates.

Makefile
config.mk
makefiles/consts.mk
makefiles/lint/jjb.mk
---------------------
  o config.mk - initial setup to support library and local makefiles.
  o Move jjb lint target (~test) into jjb.mk, conditional logging verbosity.

makefiles/git-submodules.mk
---------------------------
  o Restore skeleton git submodule dir(s) after 'make sterile' is used.
  o Some external repo content placed under revision control.
  o Odd state: make clean induces bogus git status 'deleted:'

jjb/api-test.yaml
-----------------
  o Lint cleanup, fixed a complaint about replacment of non-expansive !include token.

jjb/defaults.yaml
-----------------
  o jjb + LinuxFoundation submodules have gone stale.
  o note download sources for a pending upgrade.

jenkins_jobs.errors.JenkinsJobsException:
  Failed to find suitable template named '{project-name}-ci-jobs'
-----------------------------------------------------------------
  o Finding 2020 changeset(s) also fail linting with this problem.
  o Might have an intermittent failure to debug in here.
  o Several jobs have run cleanly in the interim.

Change-Id: I20a0f3f0f731d6f312e5798af6049afd2e18c1c9
diff --git a/makefiles/git-submodules.mk b/makefiles/git-submodules.mk
index a96121c..79809c3 100644
--- a/makefiles/git-submodules.mk
+++ b/makefiles/git-submodules.mk
@@ -20,24 +20,35 @@
 
 $(if $(DEBUG),$(warning ENTER))
 
+GIT ?= git
+
 ## -----------------------------------------------------------------------
 ## Intent: Checkout submodules required by ci-management
 ## -----------------------------------------------------------------------
+submodule-repo := $(null)
+submodule-repo += global-jjb
+submodule-repo += lf-ansible
+submodule-repo += packer
+
 submodule-deps := $(null)
 submodule-deps += submodules#     # named pseudo target
-submodule-deps += global-jjb
-submodule-deps += lf-ansible
-submodule-deps += packer
+submodule-deps += $(submodule-repos)
 
 .PHONY: $(submodule-deps)
 $(submodule-deps):
-	git submodule init
-	git submodule update
+	$(GIT) submodule init
+	$(GIT) submodule update
 
 ## -----------------------------------------------------------------------
+## Intent: Revert sandbox to a pristine state.
 ## -----------------------------------------------------------------------
 sterile ::
-	$(RM) -r $(submodule-deps)
+	$(RM) -r $(submodule-repos)
+
+        # FIXME:
+        #   o restore hierarchy to avoid git status 'deleted:'
+        #   o remove: externals should not be under revision control
+	$(GIT) co $(submodule-repos)
 
 ## -----------------------------------------------------------------------
 ## -----------------------------------------------------------------------