Initialize some variables that GCC 4.7 complains about. I'm not 100% sure

that the complaints are valid, or that simply zeroing them is the right fix
if they are, but at least it builds now. Should we be erroring if we don't
see a sliceLength header?

svn path=/trunk/; revision=49705

wiretap/peektagged.c

@@ -402,6 +402,9 @@ peektagged_process_header(wtap *wth, FILE_T fh, struct wtap_pkthdr *phdr,
     int skip_len = 0;
     double  t;
 
+    hdr_info.length      = 0;
+    hdr_info.sliceLength = 0;
+
     /* Extract the fields from the packet header */
     do {
 	/* Get the tag and value.