Fix 'show interface span' field length

Allow to display longer interface names, e.g. VirtualEthernet0/0/0.102
The field length (32) is now the same as for 'show interface'.

Change-Id: I1cb1efd459acb800bfaeeec40b672c8b17cd8c3d
Signed-off-by: Igor Mikhailov (imichail) <imichail@cisco.com>
diff --git a/src/vnet/span/span.c b/src/vnet/span/span.c
index b7292cf..fc923e0 100644
--- a/src/vnet/span/span.c
+++ b/src/vnet/span/span.c
@@ -206,7 +206,7 @@
 	clib_bitmap_t *b = clib_bitmap_dup_or (d, l);
 	if (header)
 	  {
-	    vlib_cli_output (vm, "%-20s %-20s  %6s   %6s", "Source", "Destination",
+	    vlib_cli_output (vm, "%-32s %-32s  %6s   %6s", "Source", "Destination",
 			     "Device", "L2");
 	    header = 0;
 	  }
@@ -219,7 +219,7 @@
 	    int l2 = (clib_bitmap_get (lrxm->mirror_ports, i) +
 		      clib_bitmap_get (ltxm->mirror_ports, i) * 2);
 
-	    vlib_cli_output (vm, "%-20v %-20U (%6s) (%6s)", s,
+	    vlib_cli_output (vm, "%-32v %-32U (%6s) (%6s)", s,
 			     format_vnet_sw_if_index_name, vnm, i,
 			     states[device], states[l2]);
 	    vec_reset_length (s);