Combined patch against master branch for the following issues:

Fixed a memory leak in ASN1_digest and ASN1_item_digest.
Reworked error handling in asn1_item_embed_new.
Fixed error handling in int_ctx_new and EVP_PKEY_CTX_dup.
Fixed a memory leak in CRYPTO_free_ex_data.
Reworked error handing in x509_name_ex_d2i, x509_name_encode and x509_name_canon.
Check for null pointer in tls_process_cert_verify.

Fixes #2103 #2104 #2105 #2109 #2111 #2115

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2342)