Support multiple file system types.

Change-Id: Icd89a7ce14ef7948dbd25bfbb17ff9d930514b00
diff --git a/common.h b/common.h
index a4acc39..5d24881 100644
--- a/common.h
+++ b/common.h
@@ -112,7 +112,7 @@
     const char* device2;      // alternative device to try if fs_type
                               // == "ext4" or "vfat" and mounting
                               // 'device' fails
-    const char* fallback_fs_type;
+    const char* fs_type2;
 } Volume;
 
 #endif  // RECOVERY_COMMON_H