Avoid mod_java on Debian wheezy

We're already avoiding it on sid and jessie; now we're hitting build
failures with it on wheezy.

ref: FS-6811

debian/bootstrap.sh

@@ -41,6 +41,7 @@ avoid_mods_jessie=(
   languages/mod_java
 )
 avoid_mods_wheezy=(
+  languages/mod_java
 )
 avoid_mods_squeeze=(
   formats/mod_vlc