git-curl-compat: remove check for curl 7.53.0

libcurl 7.53.0 was released in February 2017, which is over seven years
ago, and no major operating system vendor is still providing security
support for it.  Debian 10 and Ubuntu 18.04, both of which are out of
mainstream security support, have supported a newer version, and RHEL 8,
which is still in support, also has a newer version.

Remove the check for this version and use this functionality
unconditionally.

Signed-off-by: brian m. carlson <[email protected]>
Signed-off-by: Taylor Blau <[email protected]>

Author: bk2204

git-curl-compat.h

@@ -28,14 +28,6 @@
  * introduced, oldest first, in the official version of cURL library.
  */
 
-/**
- * CURL_SSLVERSION_TLSv1_3 was added in 7.53.0, released in February
- * 2017.
- */
-#if LIBCURL_VERSION_NUM >= 0x073400
-#define GIT_CURL_HAVE_CURL_SSLVERSION_TLSv1_3 1
-#endif
-
 /**
  * CURLSSLSET_{NO_BACKENDS,OK,TOO_LATE,UNKNOWN_BACKEND} were added in
  * 7.56.0, released in September 2017.

http.c

@@ -55,9 +55,7 @@ static struct {
 	{ "tlsv1.0", CURL_SSLVERSION_TLSv1_0 },
 	{ "tlsv1.1", CURL_SSLVERSION_TLSv1_1 },
 	{ "tlsv1.2", CURL_SSLVERSION_TLSv1_2 },
-#ifdef GIT_CURL_HAVE_CURL_SSLVERSION_TLSv1_3
 	{ "tlsv1.3", CURL_SSLVERSION_TLSv1_3 },
-#endif
 };
 static char *ssl_key;
 static char *ssl_key_type;