fixed is_erased variable scope

Author: dakhnod

src/storage/storage.nrf51.c

@@ -4,6 +4,8 @@
 #include "nrf_delay.h"
 #include "feature_config.h"
 
+bool is_erased = true;
+
 FS_REGISTER_CFG(fs_config_t fs_config) =
 {
     .callback = fs_evt_handler, // Function for event callbacks.
@@ -81,8 +83,6 @@ void storage_checksum_check(){
   // read 4 more to capcure checksum
   storage_read(0x00, data, length + 4);
 
-  bool is_erased = true;
-
   for(uint32_t i = 0; i < length; i++){
     if(data[i] != 0xFF){
       is_erased = false;