vlib: fix coverity warning

Remove now unused computation result.

Type: fix
Fixes: 3f8b8d30cade20afa8975a5e7a6d79346cec8f3e
Signed-off-by: Klement Sekera <ksekera@cisco.com>
Change-Id: Iea142cb044d31e364fdc5b8b6dd69681e77d745f
diff --git a/src/vlib/node_cli.c b/src/vlib/node_cli.c
index d7c7d11..77fef77 100644
--- a/src/vlib/node_cli.c
+++ b/src/vlib/node_cli.c
@@ -564,7 +564,6 @@
 	      n_clocks += l;
 
 	      v = n->stats_total.vectors - n->stats_last_clear.vectors;
-	      c = n->stats_total.calls - n->stats_last_clear.calls;
 
 	      switch (n->type)
 		{