### Please describe the problem.

I get no such file errors when using WORM backend on files with a certain name. Doesn't like brackets?

Default backend is fine (see output below).

### What steps will reproduce the problem?

See additional info

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

git-annex version: 5.20140613-g5587055
On Windows 8.1
Tried with both Windows command prompt and Git Bash shell.

### Please provide any additional information below.

[[!format sh """
# If you can, paste a complete transcript of the problem occurring here.
# If the problem is with the git-annex assistant, paste in .git/annex/daemon.log

git config --add annex.backends WORM
git annex add extras

add extras/Extra Content - Reason Drum Takes/DT Key Map.pdf ok
add extras/Extra Content - Reason Drum Takes/DT Read Me.pdf ok
add extras/Extra Content - Reason Drum Takes/DT7 Rock - Love  (136).reason ok
add extras/Extra Content - Reason Drum Takes/DT7 Rock - Peace  (200).reason ok
add extras/Extra Content - Reason Drum Takes/Kit Samples/1. Bass Drum mic (BD)/DT6_BD_Bd_RG_R_G06.aif
git-annex: C:\Studio\.git\annex\objects\b43\d6d\WORM-s178174-m1363015489--extras%Extra Content - Reason Drum Takes%Kit S
amples%1. Bass Drum mic ,40BD,41%DT6_BD_Bd_RG_R_G06.aif\WORM-s178174-m1363015489--extras%Extra Content - Reason Drum Tak
es%Kit Samples%1. Bass Drum mic ,40BD,41%DT6_BD_Bd_RG_R_G06.aif.cache: openFile: does not exist (No such file or directo
ry)
failed
add extras/Extra Content - Reason Drum Takes/Kit Samples/1. Bass Drum mic (BD)/DT6_BD_Bd_RG_R_G09.aif
git-annex: C:\Studio\.git\annex\objects\e90\b5c\WORM-s199108-m1363015489--extras%Extra Content - Reason Drum Takes%Kit S
amples%1. Bass Drum mic ,40BD,41%DT6_BD_Bd_RG_R_G09.aif\WORM-s199108-m1363015489--extras%Extra Content - Reason Drum Tak
es%Kit Samples%1. Bass Drum mic ,40BD,41%DT6_BD_Bd_RG_R_G09.aif.cache: openFile: does not exist (No such file or directo
ry)
failed
add extras/Extra Content - Reason Drum Takes/Kit Samples/1. Bass Drum mic (BD)/DT6_BD_Bd_RG_R_G14.aif
git-annex: C:\Studio\.git\annex\objects\995\4e7\WORM-s201570-m1363015489--extras%Extra Content - Reason Drum Takes%Kit S
amples%1. Bass Drum mic ,40BD,41%DT6_BD_Bd_RG_R_G14.aif\WORM-s201570-m1363015489--extras%Extra Content - Reason Drum Tak
es%Kit Samples%1. Bass Drum mic ,40BD,41%DT6_BD_Bd_RG_R_G14.aif.cache: openFile: does not exist (No such file or directo
ry)
failed

git config --unset annex.backends
git annex add extras

add extras/Extra Content - Reason Drum Takes/DT Key Map.pdf ok
add extras/Extra Content - Reason Drum Takes/DT Read Me.pdf ok
add extras/Extra Content - Reason Drum Takes/DT7 Rock - Love  (136).reason ok
add extras/Extra Content - Reason Drum Takes/DT7 Rock - Peace  (200).reason ok
add extras/Extra Content - Reason Drum Takes/Kit Samples/1. Bass Drum mic (BD)/DT6_BD_Bd_RG_R_G06.aif ok
add extras/Extra Content - Reason Drum Takes/Kit Samples/1. Bass Drum mic (BD)/DT6_BD_Bd_RG_R_G09.aif ok
add extras/Extra Content - Reason Drum Takes/Kit Samples/1. Bass Drum mic (BD)/DT6_BD_Bd_RG_R_G14.aif ok

# End of transcript or log.
"""]]
