dropbear: move failsafe code out of base-files

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Failsafe code of dropbear should be in the dropbear package not the
base-files package.

Signed-off-by: Kyle Copperfield <kmcopper@danwin1210.me>

package/network/services/dropbear/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=dropbear
 PKG_VERSION:=2019.78
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:= \
@@ -158,6 +158,7 @@ define Package/dropbear/install
 	$(INSTALL_BIN) ./files/dropbear.init $(1)/etc/init.d/dropbear
 	$(INSTALL_DIR) $(1)/usr/lib/opkg/info
 	$(INSTALL_DIR) $(1)/etc/dropbear
+	$(INSTALL_DIR) ./files/dropbear.failsafe $(1)/lib/preinit/99_10_failsafe_dropbear
 	$(if $(CONFIG_DROPBEAR_ECC),touch $(1)/etc/dropbear/dropbear_ecdsa_host_key)
 	touch $(1)/etc/dropbear/dropbear_rsa_host_key
 endef

package/network/services/dropbear/files/dropbear.failsafe

@@ -0,0 +1,8 @@
+#!/bin/sh
+
+failsafe_dropbear () {
+	dropbearkey -t rsa -s 1024 -f /tmp/dropbear_failsafe_host_key
+	dropbear -r /tmp/dropbear_failsafe_host_key <> /dev/null 2>&1
+}
+
+boot_hook_add failsafe failsafe_dropbear