Fix for gcc7

When building VPP code with gcc7 a warning (threated as error) is encountered and the build fails.
This patch addressed the compilation issue.

Change-Id: I49af9288a84d91ec8145da07c00aefb5333ec418
Signed-off-by: Marco Varlese <marco.varlese@suse.com>
diff --git a/src/vnet/policer/xlate.c b/src/vnet/policer/xlate.c
index 74a6eb2..b1c055e 100644
--- a/src/vnet/policer/xlate.c
+++ b/src/vnet/policer/xlate.c
@@ -1316,7 +1316,7 @@
     }
 
   if ((hw->rfc == IPE_RFC_RFC4115) &&
-      !(hw->peak_rate_man << hw->rate_exp) && !(hw->extd_bkt_limit_man))
+      (hw->peak_rate_man << hw->rate_exp) == 0 && !(hw->extd_bkt_limit_man))
     {
       /*
        * For a 1R2C, we set EIR = 0, EB = 0