config: remove the xft-config.in file from EXTRA_DIST

Automake always includes it in the tarball.
Signed-off-by: Gaetan Nadon <memsize@videotron.ca>

Makefile.am

@@ -29,7 +29,6 @@ pkgconfig_DATA = xft.pc
 CLEANFILES = xft-config
 
 MAINTAINERCLEANFILES = ChangeLog INSTALL
-EXTRA_DIST = xft-config.in
 
 .PHONY: ChangeLog INSTALL