def-use: fix adding data dep. edge for global variables
def-use: fix adding data dep. edge for global variables

If the global variable is initialized, we haven't added
the edge correctly.

Signed-off-by: Marek Chalupa <2ec68d8033ee11c75b31c3efa204dbc26c692ff1@fi.muni.cz>

mchalupa/dg,mchalupa/dg,mchalupa/dg,mchalupa/dg