Description of problem:
There is a documented option 'curve' for stunnel config file, but it is ignored if stunnel is run in client mode ('client = yes').

Version-Release number of selected component (if applicable):
# rpm -q stunnel
stunnel-4.56-4.el7.x86_64
# openssl version
OpenSSL 1.0.2-beta3 25 Sep 2014
(note I am using newer vesion of openssl for debugging)

How reproducible:
always

Steps to Reproduce:
1. openssl ecparam -genkey -name secp384r1 -out ca.key
2. openssl req -x509 -batch -new -key ca.key -out ca.cert -subj '/CN=ca'
3. openssl ecparam -genkey -name secp384r1 -out server.key
4. openssl req -batch -new -key server.key -out server.csr -subj "/CN=server"
5. openssl x509 -req -CAkey ca.key -CA ca.cert -CAcreateserial -in server.csr -out server.cert
6. openssl s_server -www -key server.key -cert server.cert -CAfile ca.cert -tls1_2 -sigalgs ECDSA+SHA384:ECDSA+SHA256 -Verify 1 -cipher ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384
(other console:)
7. cat >stunnel.conf <<_EOF
foreground = yes
fips = no
[test]
client = yes
accept = 9999
connect = localhost:4433
sslVersion = TLSv1.2
curve = secp384r1         ; <<<<< HERE WE SPECIFY THE CURVE
_EOF
8. stunnel stunnel.conf
(yet another console:)
9. curl localhost:9999


Actual results:
...
Shared Elliptic curves: P-521:P-384:P-256
...

Expected results:
...
Shared Elliptic curves: P-384
...

Additional info:

Specifying 'curves' option work in server mode.