Comment 2 for bug 376051

This patch add support for "openssl rsa -noout -modulus" and
"openssl dsa -noout -modulus". The patch applies on to of the
"-check" patch.

X509 seem to use "get_" in it's method names, but
PKey does not (see type()). This patch continues that
convention, but I'm open to change.

This patch duplicates the _runopenssl() function
definition in it's test case, but there is clearly
a better solution, although it would be
harder to merge.