git: avoid calling aliased builtins via their dashed form

This is one of the few places where Git violates its own deprecation of
the dashed form. It is not necessary, either.

As of 595d59e2 (git.c: ignore pager.* when launching builtin as
dashed external, 2017-08-02), Git wants to ignore the pager.* config
setting when expanding aliases. So let's strip out the
check_pager_config(<command-name>) call from the copy-edited code.

This code actually made it into upstream git.git already, but it was
disabled in `#if 0 ... #endif` guards so far.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

git.c

@@ -743,8 +743,6 @@ static int run_argv(int *argcp, const char ***argv)
 		 */
 		if (!done_alias)
 			handle_builtin(*argcp, *argv);
-
-#if 0 // TODO In GFW, need to amend a7924b655e940b06cb547c235d6bed9767929673 to include trace2_ and _tr2 lines.
 		else if (get_builtin(**argv)) {
 			struct argv_array args = ARGV_ARRAY_INIT;
 			int i;
@@ -779,7 +777,6 @@ static int run_argv(int *argcp, const char ***argv)
 				exit(i);
 			die("could not execute builtin %s", **argv);
 		}
-#endif // a7924b655e940b06cb547c235d6bed9767929673
 
 		/* .. then try the external ones */
 		execv_dashed_external(*argv);