Backed out the suspend_process_for_ptrace change.
Fixed a couple of races in ptrace code.

diff --git a/server/debugger.c b/server/debugger.c
index 377b4b3..bde3444 100644
--- a/server/debugger.c
+++ b/server/debugger.c
@@ -411,7 +411,7 @@
     for (thread = debugger; thread; thread = thread->process->debugger)
         if (thread->process == process) goto error;
 
-    suspend_process_for_ptrace( process );
+    suspend_process( process );
 
     /* we must have been able to attach all threads */
     for (thread = process->thread_list; thread; thread = thread->proc_next)