Revert "iseries: stop scanning a unicode string when the null terminator is hit."

This reverts commit c599e49028.

Reason for revert: This completely fails to recognize Unicode iSeries dumps.

Change-Id: Ie31141879b1bc3608a5dfdcba6887bb6f0018a47
Reviewed-on: https://code.wireshark.org/review/32568
Reviewed-by: Guy Harris <guy@alum.mit.edu>

wiretap/iseries.c

@@ -984,7 +984,7 @@ iseries_UNICODE_to_ASCII (guint8 * buf, guint bytes)
             *bufptr = buf[i];
             bufptr++;
         }
-      if (buf[i] == 0x0A || buf[i] == 0x0)
+      if (buf[i] == 0x0A)
         return i;
     }
   return i;