Add and use bin2img for creating images for tests

Add tests which exercise image pulling, listing, and removal.  When running
tests, prepopulate the store with an image with the default infrastructure
container's name, using the locally-built "pause" binary, so that tests won't
have to pull it down from the network.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>

Makefile

@@ -44,6 +44,9 @@ conmon:
 pause:
 	make -C $@
 
+bin2img:
+	make -C test/$@
+
 ocid:
 ifndef GOPATH
 	$(error GOPATH is not set)
@@ -73,6 +76,7 @@ clean:
 	find . -name \#\* -delete
 	make -C conmon clean
 	make -C pause clean
+	make -C test/bin2img clean
 
 ocidimage:
 	docker build -t ${OCID_IMAGE} .
@@ -86,7 +90,7 @@ integration: ocidimage
 localintegration: binaries
 	./test/test_runner.sh ${TESTFLAGS}
 
-binaries: ocid ocic kpod conmon pause
+binaries: ocid ocic kpod conmon pause bin2img
 
 MANPAGES_MD := $(wildcard docs/*.md)
 MANPAGES    := $(MANPAGES_MD:%.md=%)
@@ -180,6 +184,7 @@ install.tools: .install.gitvalidation .install.gometalinter .install.md2man
 	go get -u github.com/cpuguy83/go-md2man
 
 .PHONY: \
+	bin2img \
 	binaries \
 	clean \
 	conmon \