graph-depends: document the 'transitive' variable

Although unnecessary (we already have initialisation via the parser),
initialise the 'transitive' option, and document it at the same time.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Cc: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

support/scripts/graph-depends

@@ -37,6 +37,9 @@ mode = 0
 # Limit drawing the dependency graph to this depth. 0 means 'no limit'.
 max_depth = 0
 
+# Whether to draw the transitive dependencies
+transitive = True
+
 parser = argparse.ArgumentParser(description="Graph pacakges dependencies")
 parser.add_argument("--package", '-p', metavar="PACKAGE",
                     help="Graph the dependencies of PACKAGE")