Fix an off-by overflow one that would trigger a FORTIFY_SOURCE abort.

Lubomir Rintel <lkundrak@v3.sk>

diff -up psmisc-22.6/src/pstree.c.overflow2 psmisc-22.6/src/pstree.c
--- psmisc-22.6/src/pstree.c.overflow2	2009-08-05 01:38:32.000000000 +0200
+++ psmisc-22.6/src/pstree.c	2009-08-05 01:45:09.000000000 +0200
@@ -641,10 +641,10 @@ read_proc (void)
 		   
 		   if ((taskdir=opendir(taskpath))!=0) {
 		      /* if we have this dir, we're on 2.6 */
-		      if (!(threadname = malloc(strlen(comm) + 3))) {
+		      if (!(threadname = malloc(COMM_LEN + 1))) {
 			 exit (2);
 		      }
-		      sprintf(threadname,"{%s}",comm);
+		      sprintf(threadname,"{%.*s}", COMM_LEN - 2, comm);
 		      while ((dt = readdir(taskdir)) != NULL) {
 			 if ((thread=atoi(dt->d_name)) !=0) {
 			    if (thread != pid) {