[Buildroot] [patch] prevent make install error for avahi pkg

[Claus Klein]

make sure than target dir exist bevor instll to it:
ck

root at slax:/buildroot/package/avahi# svn diff
Index: avahi.mk
===================================================================
--- avahi.mk    (revision 20696)
+++ avahi.mk    (working copy)
@@ -151,6 +151,7 @@
 $(TARGET_DIR)/usr/sbin/avahi-autoipd: $(AVAHI_DIR)/.installed
        mkdir -p $(TARGET_DIR)/etc/avahi
        mkdir -p $(TARGET_DIR)/var/lib
+       mkdir -p $(TARGET_DIR)/usr/share/udhcpc/
        cp -af $(STAGING_DIR)/etc/avahi/avahi-autoipd.action 
$(TARGET_DIR)/etc/avahi/
        cp -af $(BASE_DIR)/package/avahi/busybox-udhcpc-default.script 
$(TARGET_DIR)/usr/share/udhcpc/default.script
        chmod 0755 $(TARGET_DIR)/usr/share/udhcpc/default.script
root at slax:/buildroot/package/avahi#