Fix --enable-static-sudoers, broken in sudo 1.9.13.

sudo_qualify_plugin() should not try to fully-qualify the path to
a statically-compiled plugin.  GitHub issue #245

src/load_plugins.c

@@ -55,6 +55,8 @@ sudo_qualify_plugin(struct plugin_info *info, char *fullpath, size_t pathsize)
 		errno = ENAMETOOLONG;
 		goto bad;
 	    }
+	    /* Plugin is static, do not fully-qualify. */
+	    debug_return_bool(true);
 	}
 #endif /* STATIC_SUDOERS_PLUGIN */