Reject elliptic curve lists of odd lengths.

The Supported Elliptic Curves extension contains a vector of NamedCurves
of 2 bytes each, so the total length must be even. Accepting odd-length
lists was observed to lead to a non-exploitable one-byte out-of-bounds
read in the latest development branches (1.0.2 and master). Released
versions of OpenSSL are not affected.

Thanks to Felix Groebert of the Google Security Team for reporting this issue.

Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit 33d5ba862939ff8db70a9e36fc9a326fab3e8d98)
Make 'make update' succeed and run it

Reviewed-by: Dr Stephen Henson <steve@openssl.org>
Add extra checks for odd-length EC curve lists.

Odd-length lists should be rejected everywhere upon parsing. Nevertheless,
be extra careful and add guards against off-by-one reads.

Also, drive-by replace inexplicable double-negation with an explicit comparison.

Reviewed-by: Matt Caswell <matt@openssl.org>
Clarify the return values for SSL_get_shared_curve.

Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit 376e2ca3e3525290619602dc6013c97c9653c037)
Fix memory leak in SSL_new if errors occur.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit 76e6509085ea96df0ca542568ee2596343711307)
Fixed memory leak in the event of a failure of BUF_MEM_grow

Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit 41bf25013032da0eeb111ce3c8fc0946c0e61c41)
Merge 'OpenSSL_1_0_2-stable' into 1.0.2-chacha