build,IB: reload packages/ only if existing

With the fix of external kmod feeds it is possible to ship the
ImageBuilder without any packages except the pseudo packages kernel and
libc. Therefore the local package feeds becomes optional.

This commit adds a check to the package_reload function to only run if
the local feed is existing.

Signed-off-by: Paul Spooren <[email protected]>

target/imagebuilder/files/Makefile

@@ -138,7 +138,10 @@ package_index: FORCE
 	$(OPKG) update >&2 || true
 
 package_reload:
-	if [ ! -f "$(PACKAGE_DIR)/Packages" ] || [ ! -f "$(PACKAGE_DIR)/Packages.gz" ] || [ "`find $(PACKAGE_DIR) -cnewer $(PACKAGE_DIR)/Packages.gz`" ]; then \
+	if [ -d "$(PACKAGE_DIR)" ] && ( \
+			[ ! -f "$(PACKAGE_DIR)/Packages" ] || \
+			[ ! -f "$(PACKAGE_DIR)/Packages.gz" ] || \
+			[ "`find $(PACKAGE_DIR) -cnewer $(PACKAGE_DIR)/Packages.gz`" ] ); then \
 		echo "Package list missing or not up-to-date, generating it." >&2 ;\
 		$(MAKE) package_index; \
 	else \