I just ran into a very similar error (for which this answer is the top google result) – the solution was in a comment by @Liviu Chircu
The solution was to put the .git on the end of the url
git clone http://myURL/projectname
Cloning into 'projectname'...
error: RPC failed; result=22, HTTP code = 404
fatal: The remote end hung up unexpectedly
However:
git clone http://myURL/projectname.git
succeeded.
The strange thing is that the original URL without .git succeeded on two linux machines and a windows desktop, but failed on a third linux machine. Including .git makes it work on all machines.