xbps_init() now sets rootdir, cachedir and flags.

That means that the following functions were removed:
	- xbps_set_{cachedir,flags,rootdir}.
	- xbps_get_{cachedir,flags,rootdir}.

With this change fixed an obvious typo that made -c argument to not work,
and now the cache directory is an absolute path not relative to rootdir.

include/xbps_api_impl.h

@@ -74,12 +74,6 @@
 
 __BEGIN_DECLS
 
-/**
- * @private
- * From lib/initend.c
- */
-const struct xbps_handle HIDDEN *xbps_handle_get(void);
-
 /**
  * @private
  * From lib/download.c