wafsamba/symbols: change regex to match both rpath and runpath for different readelf...

wafsamba/symbols: change regex to match both rpath and runpath for different readelf output

In `wafsamba.dumplicate_symbols` test, it will use Popen to call:

    readelf --dynamic bin/default/source3/lib/netapi/examples/netlogon/netlogon_control2

then try to find rpath lib lines from output with regex:

    re_rpath     = re.compile(b'Library rpath: \[(.*)\]')

In ubuntu 14.04 docker image, which current CI is using, the actual output
from `readelf` is `runpath` instead of 'rpath':

    ...
    Library runpath: [/home/gitlab-runner/samba/bin/shared:/home/gitlab-runner/samba/bin/shared/private]\n'
    ...

So the regex never matched, and hide a bug.

In Ubuntu 1604 docker image, the output changes to `rpath` and matched the
regex, which expose the error in previous commit.

Improve the regex to match both `rpath` and `runpath`.

Signed-off-by: Joe Guo <joeg@catalyst.net.nz>
Reviewed-by: Alexander Bokovoy <ab@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>