Include setjmp.h in sudoers.h

Move error_jmp into plugin_error.c
Rename sudoers_plugin_cleanup sudoers_cleanup
Make sudoers warning/error functions work when sudo_conv is NULL

plugins/sudoers/logging.c

@@ -57,7 +57,6 @@
 #include <ctype.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <setjmp.h>
 
 #include "sudoers.h"
 
@@ -528,7 +527,7 @@ log_fatal(int flags, const char *fmt, ...)
     va_end(ap);
 
     /* Exit the plugin. */
-    sudoers_plugin_cleanup(0);
+    sudoers_cleanup(0);
     sudo_debug_exit(__func__, __FILE__, __LINE__, sudo_debug_subsys);
     siglongjmp(error_jmp, 1);
 }