Fix copy-paste error

One additional line was supposed to have been copied.  By luck, this
error had still let the remainder of the recipe function, but it's
better to not leave luck in place here.

Signed-off-by: Alex Nelson <alexander.nelson@nist.gov>

Makefile

@@ -31,6 +31,7 @@ all: \
 	test -r dependencies/collections-ontology/README.md \
 	  || git submodule update \
 	    --init \
+	    dependencies/collections-ontology
 	# error ontology
 	test -r dependencies/error/README.md \
 	  || git submodule update \