use BB_EXECVP_or_die where appropriate

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

init/bootchartd.c

@@ -441,8 +441,7 @@ int bootchartd_main(int argc UNUSED_PARAM, char **argv)
 		pid_t pid = xvfork();
 		if (pid == 0) { /* child */
 			argv += 2;
-			execvp(argv[0], argv);
-			bb_perror_msg_and_die("can't execute '%s'", argv[0]);
+			BB_EXECVP_or_die(argv);
 		}
 		/* parent */
 		waitpid(pid, NULL, 0);

networking/nc_bloaty.c

@@ -268,8 +268,7 @@ static int doexec(char **proggie)
 	dup2(0, 1);
 	/* dup2(0, 2); - do we *really* want this? NO!
 	 * exec'ed prog can do it yourself, if needed */
-	execvp(proggie[0], proggie);
-	bb_perror_msg_and_die("can't execute '%s'", proggie[0]);
+	BB_EXECVP_or_die(proggie);
 }
 
 /* connect_w_timeout:

selinux/runcon.c

@@ -132,6 +132,5 @@ int runcon_main(int argc UNUSED_PARAM, char **argv)
 		bb_error_msg_and_die("can't set up security context '%s'",
 				     context_str(con));
 
-	execvp(argv[0], argv);
-	bb_perror_msg_and_die("can't execute '%s'", argv[0]);
+	BB_EXECVP_or_die(argv);
 }