fdstream: avoid child process leak on error

By requesting the pid in virCommandRunAsync, fdstream was claiming
that it would manually wait for the process.  But on the failure
path, the child process was being leaked.

* src/fdstream.c (virFDStreamOpenFileInternal): Auto-reap child.

src/fdstream.c

@@ -31,7 +31,6 @@
 # include <sys/un.h>
 #endif
 #include <netinet/in.h>
-#include <signal.h>
 
 #include "fdstream.h"
 #include "virterror_internal.h"
@@ -514,7 +513,6 @@ virFDStreamOpenFileInternal(virStreamPtr st,
     struct stat sb;
     virCommandPtr cmd = NULL;
     int errfd = -1;
-    pid_t pid = 0;
 
     VIR_DEBUG("st=%p path=%s flags=%x offset=%llu length=%llu mode=%o delete=%d",
               st, path, flags, offset, length, mode, delete);
@@ -588,7 +586,7 @@ virFDStreamOpenFileInternal(virStreamPtr st,
         }
         virCommandSetErrorFD(cmd, &errfd);
 
-        if (virCommandRunAsync(cmd, &pid) < 0)
+        if (virCommandRunAsync(cmd, NULL) < 0)
             goto error;
 
         VIR_FORCE_CLOSE(childfd);
@@ -611,10 +609,6 @@ virFDStreamOpenFileInternal(virStreamPtr st,
     return 0;
 
 error:
-#ifndef WIN32
-    if (pid)
-        kill(SIGTERM, pid);
-#endif
     virCommandFree(cmd);
     VIR_FORCE_CLOSE(fds[0]);
     VIR_FORCE_CLOSE(fds[1]);