waf: fix install directory of inprocess example clients

git-svn-id: http://subversion.jackaudio.org/jack/jack2/trunk/jackmp@2478 0c269be4-1314-0410-8aa9-9f06e86f4224

example-clients/wscript

@@ -84,3 +84,5 @@ def build(bld):
         lib.includes = ['../common/jack', '../common']
         lib.target = example_lib
         lib.source = example_lib_source
+        lib.inst_var = bld.env()['ADDON_DIR']
+        lib.inst_dir = '/'