[netboot] add ssh keys before starting bootserver

Change-Id: I5c8bdb12644d6ba4ec1fff7486bd4494911c5045
diff --git a/tools/devshell/netboot b/tools/devshell/netboot
index 03fdeb5..65290ccb 100755
--- a/tools/devshell/netboot
+++ b/tools/devshell/netboot
@@ -18,4 +18,11 @@
   name_args+=("-n" "${name}")
 fi
 
-exec "${FUCHSIA_BUILD_DIR}/netboot.sh" "${name_args[@]}" "$@"
+tmpdir="${FUCHSIA_BUILD_DIR}.netboot.tmp"
+mkdir "${tmpdir}"
+trap 'rm -rf "${tmpdir}"' EXIT
+
+cp "${FUCHSIA_BUILD_DIR}/netboot.sh" "${tmpdir}"
+"${ZIRCON_TOOLS_DIR}/zbi" -o "${tmpdir}/netboot.zbi" "${FUCHSIA_BUILD_DIR}/netboot.zbi" "--entry=data/ssh/authorized_keys=${FUCHSIA_DIR}/.ssh/authorized_keys"
+
+"${tmpdir}/netboot.sh" "${name_args[@]}" "$@"