libsepol/cil: Update symtab nprim field when adding or removing datums

This field is suppose to be used to track the number of primary names in
the symtab. It was not being updated or used.

Increment the nprim field when a new datum is added to the symtab and
decrement the field when a datum is removed.

Signed-off-by: James Carter <jwcart2@gmail.com>

libsepol/cil/src/cil_symtab.c

@@ -92,6 +92,7 @@ int cil_symtab_insert(symtab_t *symtab, hashtab_key_t key, struct cil_symtab_dat
 		datum->name = key;
 		datum->fqn = key;
 		datum->symtab = symtab;
+		symtab->nprim++;
 		cil_list_append(datum->nodes, CIL_NODE, node);
 	} else if (rc == SEPOL_EEXIST) {
 		cil_list_append(datum->nodes, CIL_NODE, node);
@@ -111,6 +112,7 @@ void cil_symtab_remove_datum(struct cil_symtab_datum *datum)
 	}
 
 	hashtab_remove(symtab->table, datum->name, NULL, NULL);
+	symtab->nprim--;
 	datum->symtab = NULL;
 }