[source] imagebuilder: remove existing debug kernel image

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/619c8fa92209fb1a30d6e68a59a13aaa102a764c

commit 619c8fa92209fb1a30d6e68a59a13aaa102a764c
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Fri Jan 13 19:22:09 2017 +0100

    imagebuilder: remove existing debug kernel image
    
    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 13eed7e..d891aab 100644
--- a/target/imagebuilder/Makefile
+++ b/target/imagebuilder/Makefile
@@ -67,6 +67,7 @@ endif
 	-cp $(KERNEL_BUILD_DIR)/* $(IB_KDIR)/ # don't copy subdirectories here
 	-cp $(LINUX_DIR)/.config $(IB_LDIR)/
 	rm -f $(IB_KDIR)/root.*
+	rm -f $(IB_KDIR)/vmlinux.debug
 	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; \