bump version: work towards 7.21.7

Curl and libcurl 7.21.6

Curl and libcurl 7.21.7

 Public curl releases:         122

 Public curl releases:         123

 Command line options:         144

 curl_easy_setopt() options:   186

 Public functions in libcurl:  58

 Known libcurl bindings:       39

 Contributors:                 865

 Contributors:                 868

This release includes the following changes:

 o Added --tr-encoding and CURLOPT_TRANSFER_ENCODING

 o

This release includes the following bugfixes:

 o curl-config: fix --version

 o curl_easy_setopt.3: CURLOPT_PROXYTYPE clarification

 o use HTTPS properly after CONNECT

 o SFTP: close file before post quote operations

 o 

This release includes the following known bugs:

/* This is the version number of the libcurl package from which this header

   file origins: */

#define LIBCURL_VERSION "7.21.6-DEV"

#define LIBCURL_VERSION "7.21.7-DEV"

/* The numeric version number is also available "in parts" by using these

   defines: */

#define LIBCURL_VERSION_MAJOR 7

#define LIBCURL_VERSION_MINOR 21

#define LIBCURL_VERSION_PATCH 6

#define LIBCURL_VERSION_PATCH 7

/* This is the numeric version of the libcurl version number, meant for easier

   parsing and comparions by programs. The LIBCURL_VERSION_NUM define will

   and it is always a greater number in a more recent release. It makes

   comparisons with greater than and less than work.

*/

#define LIBCURL_VERSION_NUM 0x071506

#define LIBCURL_VERSION_NUM 0x071507

/*

 * This is the date and time when the full source package was created. The