### Please describe the problem.

I'm sending a stream of keys and filenames to git-annex fromkey on stdin, and it errors out with "git-annex: <stdin>: hGetContents: invalid argument (invalid byte sequence)". On the other hand yipdw tried to reproduce this and it worked fine for him, so I must be doing something wrong.

I have LANG=en_US.UTF-8 set in my environment, if that matters.

### What steps will reproduce the problem?

[[!format sh """
echo "MD5-s3263532--0b4d070eff7baa8ef314ca330aecb71f é" | git-annex fromkey
"""]]

### What version of git-annex are you using? On what operating system?

[[!format sh """
git-annex version: 6.20161118-g0a34f08
build flags: Assistant Webapp Pairing Testsuite S3(multipartupload)(storageclasses) WebDAV Inotify DBus DesktopNotify XMPP ConcurrentOutput TorrentParser MagicMime Feeds Quvi
key/value backends: SHA256E SHA256 SHA512E SHA512 SHA224E SHA224 SHA384E SHA384 SHA3_256E SHA3_256 SHA3_512E SHA3_512 SHA3_224E SHA3_224 SHA3_384E SHA3_384 SKEIN256E SKEIN256 SKEIN512E SKEIN512 SHA1E SHA1 MD5E MD5 WORM URL
remote types: git gcrypt S3 bup directory rsync web bittorrent webdav tahoe glacier ddar hook external
local repository version: 5
supported repository versions: 3 5 6
upgrade supported from repository versions: 0 1 2 3 4 5
operating system: linux x86_64
"""]]

### Please provide any additional information below.

Note that this is indeed valid utf-8:

[[!format sh """
 db48x  ~  projects  IA.BAK-server  echo "é" | hexdump -C
00000000  c3 a9 0a                                          |...|
00000003
"""]]

> Despite my strange inability to reproduce these, there's really only one
> thing that can fix it, namely using fileEncoding. Now done for all batch
> and stdin reading stuff. [[fixed|done]] I suppose. --[[Joey]]
