BUG/MINOR: cli: "show cli sockets" would always report process 64

Another small bug in "show cli sockets" made the last fix always report
process 64 due to a signedness issue in the shift operation when building
the mask.
diff --git a/src/cli.c b/src/cli.c
index 6fd7455..a875d38 100644
--- a/src/cli.c
+++ b/src/cli.c
@@ -798,9 +798,8 @@
 
 						if (bind_conf->bind_proc != 0) {
 							int pos;
-
 							for (pos = 0; pos < 8 * sizeof(bind_conf->bind_proc); pos++) {
-								if (bind_conf->bind_proc & (1 << pos)) {
+								if (bind_conf->bind_proc & (1UL << pos)) {
 									chunk_appendf(&trash, "%d,", pos+1);
 								}
 							}