object-store: drop loose_object_path()

The function `loose_object_path()` is a trivial wrapper around
`odb_loose_path()`, with the only exception that it always uses the
primary object database of the given repository. This doesn't really add
a ton of value though, so let's drop the function and inline it at every
callsite.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

object-file.h

@@ -25,6 +25,10 @@ int index_path(struct index_state *istate, struct object_id *oid, const char *pa
 
 struct object_directory;
 
+/*
+ * Put in `buf` the name of the file in the local object database that
+ * would be used to store a loose object with the specified oid.
+ */
 const char *odb_loose_path(struct object_directory *odb,
 			   struct strbuf *buf,
 			   const struct object_id *oid);