pmap: avoid depending on an uninitialised value.

It's possible for the first entry that this reads from /proc/*/smaps to
start with a map_desc-less line like this:

7fa71b77d000-7fa71c288000 rw-p 00000000 00:00 0

in which case sscanf will only read up to inode, and it won't set c; the
code below would then incorrectly discard the next ("Size:") line.

(With GCC 4.9.0, this bug causes the "pmap extra extended output" test
to fail for me.)

pmap.c

@@ -314,6 +314,7 @@ static void print_extended_maps (FILE *f)
 	while (ret != NULL) {
 		/* === READ MAPPING === */
 		map_desc[0] = '\0';
+		c = '\n';
 		nfields = sscanf(mapbuf,
 				 "%"NUML"[0-9a-f]-%"NUML"[0-9a-f] "
 				 "%"DETL"s %"NUML"[0-9a-f] "