Revert "configure.ac: Enable color-test automake option."

This reverts commit 380fc82a.

This fixes bootstrap with automake 1.9 and 1.10.

configure.ac

@@ -22,7 +22,7 @@ AC_CONFIG_LIBOBJ_DIR(compat)
 AC_CANONICAL_BUILD
 AC_CANONICAL_HOST
 
-AM_INIT_AUTOMAKE(tar-ustar color-tests)
+AM_INIT_AUTOMAKE(tar-ustar)
 AM_CONFIG_HEADER(config.h)
 
 # Disable with "./configure --disable-silent-rules" or "make V=1"