clean-up trailing whitespace (#453)

These changes have been mostly auto-generated with:

	find . -type f -print0 | xargs -0 perl -pi -e 's/ +$//'

Signed-off-by: Radostin Stoyanov <rstoyanov@fedoraproject.org>

exercises/firewall/firewall.p4

@@ -108,7 +108,7 @@ parser MyParser(packet_in packet,
 ************   C H E C K S U M    V E R I F I C A T I O N   *************
 *************************************************************************/
 
-control MyVerifyChecksum(inout headers hdr, inout metadata meta) {   
+control MyVerifyChecksum(inout headers hdr, inout metadata meta) {
     apply {  }
 }
 
@@ -154,7 +154,7 @@ control MyIngress(inout headers hdr,
         hdr.ethernet.dstAddr = dstAddr;
         hdr.ipv4.ttl = hdr.ipv4.ttl - 1;
     }
-    
+
     table ipv4_lpm {
         key = {
             hdr.ipv4.dstAddr: lpm;
@@ -184,7 +184,7 @@ control MyIngress(inout headers hdr,
         size = 1024;
         default_action = NoAction();
     }
-    
+
     apply {
         if (hdr.ipv4.isValid()){
             ipv4_lpm.apply();
@@ -232,10 +232,10 @@ control MyEgress(inout headers hdr,
 
 control MyComputeChecksum(inout headers  hdr, inout metadata meta) {
      apply {
-	update_checksum(
-	    hdr.ipv4.isValid(),
+        update_checksum(
+            hdr.ipv4.isValid(),
             { hdr.ipv4.version,
-	      hdr.ipv4.ihl,
+              hdr.ipv4.ihl,
               hdr.ipv4.diffserv,
               hdr.ipv4.totalLen,
               hdr.ipv4.identification,