Use unique_ptr and unique_fd to manager FDs.

Clean up leaky file descriptors in uncrypt/uncrypt.cpp. Add unique_fd
for open() and unique_file for fopen() to close FDs on destruction.

Bug: 21496020
Change-Id: I0174db0de9d5f59cd43b44757b8ef0f5912c91a2

uncrypt/Android.mk

@@ -20,6 +20,8 @@ LOCAL_CLANG := true
 
 LOCAL_SRC_FILES := uncrypt.cpp
 
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/..
+
 LOCAL_MODULE := uncrypt
 
 LOCAL_STATIC_LIBRARIES := libbase liblog libfs_mgr libcutils