Call _exit() instead of exit() on child failure.

As explained on man _exit:

"The  function  _exit()  terminates  the calling process "immediately".
Any open file descriptors belonging to the process are closed;"

If exit() is called instead, the resulting zip file will be corrupted.

BUG: 27900023
BUG: 27804637
Change-Id: I6591749603753d6016f350c629b7082cf6780ae2
diff --git a/cmds/dumpstate/utils.cpp b/cmds/dumpstate/utils.cpp
index 8129852..8c0e840 100644
--- a/cmds/dumpstate/utils.cpp
+++ b/cmds/dumpstate/utils.cpp
@@ -746,7 +746,8 @@
         // it's safer to exit dumpstate.
         MYLOGD("execvp on command '%s' failed (error: %s)", command, strerror(errno));
         fflush(stdout);
-        exit(EXIT_FAILURE);
+        // Must call _exit (instead of exit), otherwise it will corrupt the zip file.
+        _exit(EXIT_FAILURE);
     }
 
     /* handle parent case */