[source] imagebuilder: remove existing root filesystem images

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/d1514e8f846ae629614abea7dc4611437698adfe

commit d1514e8f846ae629614abea7dc4611437698adfe
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Fri Jan 13 19:21:31 2017 +0100

    imagebuilder: remove existing root filesystem images
    
    Reduces tarball size and improves build time
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 target/imagebuilder/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/target/imagebuilder/Makefile b/target/imagebuilder/Makefile
index 8a7c209..13eed7e 100644
--- a/target/imagebuilder/Makefile
+++ b/target/imagebuilder/Makefile
@@ -66,6 +66,7 @@ endif
 		$(PKG_BUILD_DIR)/target/linux/*/patches{,-*}
 	-cp $(KERNEL_BUILD_DIR)/* $(IB_KDIR)/ # don't copy subdirectories here
 	-cp $(LINUX_DIR)/.config $(IB_LDIR)/
+	rm -f $(IB_KDIR)/root.*
 	if [ -x $(LINUX_DIR)/scripts/dtc/dtc ]; then \
 		$(INSTALL_DIR) $(IB_LDIR)/scripts/dtc; \
 		$(INSTALL_BIN) $(LINUX_DIR)/scripts/dtc/dtc $(IB_LDIR)/scripts/dtc/dtc; \