[patch] Fix exec utility kill behavior

[Andrew Black]

Greetings all.

Below is a one line patch (and changelog) to fix a bad mistake in the 
kill behavior of the exec utility.  I started looking into this issue as 
a result of the locale or localedef utility apparently hanging on AIX. 
This doesn't fix that issue, but it should kill things correctly.

--Andrew Black

Log:
	exec.cpp (wait_for_child): Correct mistake in kill() call to kill child 
process group rather than child process.

Index: exec.cpp
===================================================================
--- exec.cpp    (revision 431382)
+++ exec.cpp    (working copy)
@@ -458,7 +458,7 @@
                 }

                 /* ignore kill errors (perhaps should record them)*/
-                (void)kill (child_pid, signals [siginx]);
+                (void)kill (-child_pid, signals [siginx]);

                 /* Record the signal used*/
                 state.killed = signals [siginx];