Trivial fixes on error paths

* strace.c (startup_attach): Emit message on fork() failure.
(startup_child): Remove non-informative comment.
* util.c (ptrace_restart): use perror_msg() on error instead of fprintf().

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
diff --git a/strace.c b/strace.c
index fcdae0b..722a0f0 100644
--- a/strace.c
+++ b/strace.c
@@ -424,7 +424,7 @@
 	if (daemonized_tracer) {
 		pid_t pid = fork();
 		if (pid < 0) {
-			_exit(1);
+			perror_msg_and_die("fork");
 		}
 		if (pid) { /* parent */
 			/*
@@ -641,7 +641,7 @@
 # ifndef FREEBSD
 		pause();
 # else
-		kill(pid, SIGSTOP); /* stop HERE */
+		kill(pid, SIGSTOP);
 # endif
 #else /* !USE_PROCFS */
 		if (!daemonized_tracer) {
diff --git a/util.c b/util.c
index 20311fc..0658bc0 100644
--- a/util.c
+++ b/util.c
@@ -224,8 +224,7 @@
 		msg = "CONT";
 	if (op == PTRACE_DETACH)
 		msg = "DETACH";
-	fprintf(stderr, "strace: ptrace(PTRACE_%s,1,%d): %s\n",
-			msg, sig, strerror(err));
+	perror_msg("ptrace(PTRACE_%s,1,%d)", msg, sig);
 	return -1;
 }