Remove duplicate return statements.

common/atobool.c

@@ -80,6 +80,5 @@ atobool(const char *str)
 		return 0;
 	    break;
     }
-    return -1;
     debug_return_int(-1);
 }

common/term.c

@@ -96,7 +96,6 @@ term_noecho(int fd)
 #endif
     if (tcsetattr(fd, TCSADRAIN|TCSASOFT, &term) == 0) {
 	changed = 1;
-	return 1;
 	debug_return_int(1);
     }
     debug_return_int(0);

src/exec.c

@@ -235,7 +235,6 @@ sudo_execve(struct command_details *details, struct command_status *cstat)
 	    case -1:
 		cstat->type = CMD_ERRNO;
 		cstat->val = errno;
-		return -1;
 		debug_return_int(-1);
 	    case 0:
 		/* child continues without controlling terminal */