Description of problem:
If you invoke rpmdev-extract on multiple rpms with only a relative path, then it will extract the first and then fail to find the rest.

Version-Release number of selected component (if applicable):
rpmdevtools-8.1-1.fc15.noarch

How reproducible:
100%

Steps to Reproduce:
1. rpmdev-extract [multiple relative rpms]
  
Actual results:
$ ls -s1 rpm*.rpm
976K rpm-4.9.0-9.fc15.x86_64.rpm
116K rpmdevtools-8.1-1.fc15.noarch.rpm
$ rpmdev-extract -q rpm*.rpm
Error: file does not exist: 'rpmdevtools-8.1-1.fc15.noarch.rpm'

Expected results:
All rpms extracted, as it works with full paths, e.g.
$ rpmdev-extract -q $PWD/rpm*.rpm"

Additional info:
I believe the issue is simply that the original working directory is lost when unarch() opens an rpm.  The chain of "cd" in that case is:

    cd "$2"                # the output dir ($PWD or -Cdir)
            cd "$name"     # the rpm package's name
            cd ..          # back to the base output dir
    cd - >/dev/null 2>&1   # back to $OLDPWD, which is $name !

There are number of ways to solve this.  You could normalize all the rpm paths ahead of time, so they're always found, but I think that's not quite enough to get the output in the right place too.  You could explicitly remember and restore the starting path rather than relying on "cd -".  Or you could invoke that function in a () subshell so the main working directory is not affected, e.g. (unarch "$file" "$dir")