Remove size limit for files inlined in config

Remove size limit for files inlined in config

As described in trac #484, the current inline file size limit of 10000
bytes is becoming an issue for some users.  Since RSA keys and signature
sizes are increasing, we need to adjust our limits.  As #484 reports,
10000 can be too small for PKCS#12 files with 4K RSA keys.  Instead of
postponing this issue by increasing the static limit, dynamically increase
the buffer size while reading. This keeps the memory usage limited but does
allow for larger inlined files.

Signed-off-by: Steffan Karger <steffan@karger.me>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <1430122342-11742-1-git-send-email-steffan@karger.me>
URL: http://article.gmane.org/gmane.network.openvpn.devel/9607
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit e473b7c4ce41a450645e0f89579bc25b4a7f7d49)