Updated tracehash.pl file to skip parsing of empty line from hash file

To get rid of these prints -
Use of uninitialized value $l_str in concatenation

Change-Id: I475c2471e9fde60c7413734412ada0243c1f570d
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/67590
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Sachin Gupta <sgupta2m@in.ibm.com>

src/tools/trace/tracehash.pl

@@ -6,7 +6,7 @@
 #
 # OpenPOWER sbe Project
 #
-# Contributors Listed Below - COPYRIGHT 2015,2016
+# Contributors Listed Below - COPYRIGHT 2015,2018
 # [+] International Business Machines Corp.
 #
 #
@@ -649,6 +649,11 @@ ($)
 
 	while (defined $line) {
 	    chop $line;         # remove EOL
+        if(! $line)
+        {
+	        $line = <FH>;
+            next;
+        }
 	    if($version eq "1")
 	    {
 		($l_hash, $l_file ,$l_str) = split(/\|\|/, $line);
@@ -672,7 +677,7 @@ ($)
 		}
 		if ($hashstr1 ne $hashstr2)
 		{
-		    print "*** ERROR: HASH Collision! (a_f)\n",
+		    print "*** assimilate_file: ERROR: HASH Collision! (a_f)\n",
 			  "    Two different strings have the same hash value ($l_hash)\n",
 			  "    String 1: $hash_strings_array{$l_hash}\n",
 			  "    String 2: $newstring\n";