Int cleanup

[johnnybubonic]

So, a couple inconsistencies make this module a little irksome.

First, you defined ints for the const flags (since you don't declare what type they are), but the functions take int32s so an explicit conversion is necessary; an int cannot be automatically casted to an int32.

Secondly, you had an integer overflow by using the int32s.

chattr.FS_RESERVED_FL is defined as 0x80000000, which is correct... but this is DEC 2147483648.
This is higher than Golang's int32 max by 1, which causes it to then overflow to -2147483648.

All of these are resolved by using uint32's everywhere.

[johnnybubonic]

(This will obviously break your API, but you only have one dep)

[devhaozi]

This is incorrect, it should be:

	FS_SECRM_FL        uint32 = 0x00000001 /* Secure deletion */
	FS_UNRM_FL         uint32 = 0x00000002 /* Undelete */
	FS_COMPR_FL        uint32 = 0x00000004 /* Compress file */
	FS_SYNC_FL         uint32 = 0x00000008 /* Synchronous updates */
	FS_IMMUTABLE_FL    uint32 = 0x00000010 /* Immutable file */
	FS_APPEND_FL       uint32 = 0x00000020 /* writes to file may only append */
	FS_NODUMP_FL       uint32 = 0x00000040 /* do not dump file */
	FS_NOATIME_FL      uint32 = 0x00000080 /* do not update atime */
	FS_DIRTY_FL        uint32 = 0x00000100
	FS_COMPRBLK_FL     uint32 = 0x00000200 /* One or more compressed clusters */
	FS_NOCOMP_FL       uint32 = 0x00000400 /* Don't compress */
	FS_ENCRYPT_FL      uint32 = 0x00000800 /* Encrypted file */
	FS_BTREE_FL        uint32 = 0x00001000 /* btree format dir */
	FS_INDEX_FL        uint32 = 0x00001000 /* hash-indexed directory */
	FS_IMAGIC_FL       uint32 = 0x00002000 /* AFS directory */
	FS_JOURNAL_DATA_FL uint32 = 0x00004000 /* Reserved for ext3 */
	FS_NOTAIL_FL       uint32 = 0x00008000 /* file tail should not be merged */
	FS_DIRSYNC_FL      uint32 = 0x00010000 /* dirsync behaviour (directories only) */
	FS_TOPDIR_FL       uint32 = 0x00020000 /* Top of directory hierarchies*/
	FS_HUGE_FILE_FL    uint32 = 0x00040000 /* Reserved for ext4 */
	FS_EXTENT_FL       uint32 = 0x00080000 /* Extents */
	FS_EA_INODE_FL     uint32 = 0x00200000 /* Inode used for large EA */
	FS_EOFBLOCKS_FL    uint32 = 0x00400000 /* Reserved for ext4 */
	FS_NOCOW_FL        uint32 = 0x00800000 /* Do not cow file */
	FS_INLINE_DATA_FL  uint32 = 0x10000000 /* Reserved for ext4 */
	FS_PROJINHERIT_FL  uint32 = 0x20000000 /* Create with parents projid */
	FS_RESERVED_FL     uint32 = 0x80000000 /* reserved for ext2 lib */