resolver-debug: add check in postrm for resolver-debug.sh

net/resolver-debug/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=resolver-debug
 PKG_VERSION:=0.0.1
-PKG_RELEASE:=7
+PKG_RELEASE:=8
 
 PKG_MAINTAINER:=Jan Pavlinec <jan.pavlinec@nic.cz>
 PKG_LICENSE:=GPL-3.0
@@ -49,7 +49,7 @@ define Package/resolver-debug/postrm
 #!/bin/sh
 # check if we are on real system
 if [ -z "$$IPKG_INSTROOT" ]; then
-	/etc/resolver/resolver-debug.sh remove-btn
+	[ -f /etc/resolver/resolver-debug.sh ] && /etc/resolver/resolver-debug.sh remove-btn
 fi
 endef