### Please describe the problem.
On Android, any attempt by git-annex to use the 'web' special remote won't work, instead wget will complain about the user-agent parameter. This is very annoying when I have web URLs registered for numerous files. 

### What steps will reproduce the problem?
Try to grab a file via git-annex that has an attached web URL on Android. 

### What version of git-annex are you using? On what operating system?
Latest version of git-annex app on an Android 5 tablet.

### 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


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

### Have you had any luck using git-annex before? (Sometimes we get tired of reading bug reports all day and a lil' positive end note does wonders)