Changed the failure code when TLS v1.1 and v1.2 is requested but not
supported by older OpenSSL versions, following review from libcurl
peers, and reduced the number of required preprocessor if statements.

...with the use of CURL_SSLVERSION_TLSv1_1 and CURL_SSLVERSION_TLSv1_2
being conditional on OpenSSL v1.0.1 as the appropriate flags are not
supported under earlier versions.

Commit ad34a2d5 relies on definitions that are only present in
OpenSSL v1.0.1 and up. This quick fix allows the builds that use
older versions of OpenSSL to continue building.

Bug: http://sourceforge.net/p/curl/bugs/1291
Reported-by: David Walser

According to the documentation for libssh2_userauth_list(), a NULL
return value is not necessarily an error. You must call
libssh2_userauth_authenticated() to determine if the SSH_USERAUTH_NONE
request was successful.

This fixes a segv when using sftp on a server that allows logins with an
empty password. When NULL was interpreted as an error, it would
free the session but not flag an error since the libssh2 errno would be
clear. This resulted in dereferencing a NULL session pointer.

Signed-off-by: Tyler Hall <tylerwhall@gmail.com>

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.

SecPKCS12Import() returns a few errors that are enumerated in OS X's
headers but not in iOS' headers for some reason.

After the option rename in 5df04bfa

Reported-by: Petr Pisar

Write to CURLOPT_ERRORBUFFER information about mismatch alternative
certificate subject names.

Signed-off-by: Andrej E Baranov <admin@andrej-andb.ru>

The option '--bearer' might be slightly ambiguous in name. It doesn't
create any conflict that I am aware of at the moment, however, OAUTH v2
is not the only authentication mechanism which uses "bearer" tokens.

Reported-by: Kyle L. Huff
URL: http://curl.haxx.se/mail/lib-2013-10/0064.html

This fixes a regression introduced by commit 0feeab78 limiting the speed
of SCP upload to 16384 B/s on a fast connection (such as localhost).

lib/curl_setup_once.h assumed lwIP on Windows uses 'SetLastError()' to
set network errors. It doesn't; it uses 'errno'.

When using the -w '%{http_code}' flag and simulating a Not Modified then
304 should be output.

Credit (for catching a cipher I forgot to add to the blocked ciphers list):
https://www.ssllabs.com/ssltest/viewMyClient.html