兼容glibc

Change-Id: I7b1361d8f1e3c31c2d94b31b6addc32869dee457
diff --git a/mbtk/test/others/partition_write_demo.c b/mbtk/test/others/partition_write_demo.c
index 762e49c..1256d75 100755
--- a/mbtk/test/others/partition_write_demo.c
+++ b/mbtk/test/others/partition_write_demo.c
@@ -12,7 +12,7 @@
     char buffer[102400];
     long len = -1;
     long count = 0;
-    int fd = open("/etc/file.temp", O_CREAT | O_WRONLY | O_TRUNC);
+    int fd = open("/etc/file.temp", O_CREAT | O_WRONLY | O_TRUNC, 0666);
     if(fd < 0) {
         printf("Open file error:%d\n", errno);
         return -1;