Fixes memory leak introduced in 2b9af967

Fixes https://bugs.php.net/bug.php?id=68285
Adds better handling of EC keys: OPENSSL_KEYTYPE_EC

When working with elliptic curve and openssl some functions are not
aware of the different handling.
Improvements:
- Fixes export of EC private keys
- Adds curve information to openssl_pkey_get_details

Conflicts:
	ext/openssl/openssl.c
Adds test cases for openssl EC improvements
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  Adds test cases for openssl EC improvements
  Adds better handling of EC keys: OPENSSL_KEYTYPE_EC
Merge branch 'pull-request/914' into PHP-5.5

* pull-request/914:
  Fixes memory leak introduced in 2b9af967
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  Fixes memory leak introduced in 2b9af967