icecc: Add dummy python version of set_icecc_env

Bitbakes prepend mechanism for the tasks disregards the type of the
function. Thus bitbaking recipes using python functions for configure,
compile or install steps fail due to the missing python version of
set_icecc_env.

Assuming that icecc doesn't need to be used in such situations adding
a dummy python version of set_icecc_env fixes this.

(From OE-Core rev: 365dec500166b8eb9d64c573dd7139d3a26ae445)

Signed-off-by: Tobias Henkel <tobias.henkel@bmw-carit.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/icecc.bbclass

@@ -188,6 +188,10 @@ def icc_get_and_check_tool(bb, d, tool):
     else:
         return t
 
+def set_icecc_env():
+    # dummy python version of set_icecc_env
+    return
+
 set_icecc_env() {
     if [ "x${ICECC_DISABLED}" != "x" ]
     then