pstree: fix segfault introduced by the warnings fixes

Change-Id: I159f0250285eee00b4bcc4830bf36033607f72ff
diff --git a/procps/pstree.c b/procps/pstree.c
index 934fb6e..45fce3a 100644
--- a/procps/pstree.c
+++ b/procps/pstree.c
@@ -87,7 +87,7 @@
  */
 static void ensure_buffer_capacity(int bufindex)
 {
-	if (bufindex > 0 && (unsigned) bufindex >= G.capacity) {
+	if ((unsigned)bufindex >= G.capacity) {
 		G.capacity += 0x100;
 		G.width = xrealloc(G.width, G.capacity * sizeof(G.width[0]));
 		G.more = xrealloc(G.more, G.capacity * sizeof(G.more[0]));