rpm fails to install when current dir is unaccessible

Steps To Reproduce:
as non-root:
sudo zypper -n in sshfs ; cd /var/tmp ; mkdir mnt
sshfs localhost:/ mnt && cd mnt/tmp/
sudo rpm -U --force /tmp/gvim-7.3-22.3.1.i586.rpm 
error: Unable to open current directory: Permission denied


strace shows that rpm tries to open(".") and gets -EACCESS
but in the working case, this file descriptor does not appear to be used anyway

I also experienced a (not yet reproduced) case where some cache/index was corrupted, so every subsequent zypper call would error out after installing a package, but before running post-inst scripts.