CURL_SSLVERSION_TLSv1_0, CURL_SSLVERSION_TLSv1_1,
CURL_SSLVERSION_TLSv1_2 enum values are added to force exact TLS version
(CURL_SSLVERSION_TLSv1 means TLS 1.x).
axTLS:
axTLS only supports TLS 1.0 and 1.1 but it cannot be set that only one
of these should be used, so we don't allow the new enum values.
darwinssl:
Added support for the new enum values.
SChannel:
Added support for the new enum values.
CyaSSL:
Added support for the new enum values.
Bug: The original CURL_SSLVERSION_TLSv1 value enables only TLS 1.0 (it
did the same before this commit), because CyaSSL cannot be configured to
use TLS 1.0-1.2.
GSKit:
GSKit doesn't seem to support TLS 1.1 and TLS 1.2, so we do not allow
those values.
Bugfix: There was a typo that caused wrong SSL versions to be passed to
GSKit.
NSS:
TLS minor version cannot be set, so we don't allow the new enum values.
QsoSSL:
TLS minor version cannot be set, so we don't allow the new enum values.
OpenSSL:
Added support for the new enum values.
Bugfix: The original CURL_SSLVERSION_TLSv1 value enabled only TLS 1.0,
now it enables 1.0-1.2.
Command-line tool:
Added command line options for the new values.
