khash: avoid using `kh_exist` directly

src/cache.c

@@ -127,7 +127,7 @@ static void cache_evict_entries(git_cache *cache)
 	while (evict_count > 0) {
 		khiter_t pos = seed++ % git_oidmap_end(cache->map);
 
-		if (kh_exist(cache->map, pos)) {
+		if (git_oidmap_has_data(cache->map, pos)) {
 			git_cached_obj *evict = kh_val(cache->map, pos);
 
 			evict_count--;

src/oidmap.h

@@ -37,6 +37,7 @@ GIT_INLINE(khint_t) git_oidmap_hash(const git_oid *oid)
 #define git_oidmap_valid_index(h, idx) (idx != kh_end(h))
 
 #define git_oidmap_exists(h, k) (kh_get(oid, h, k) != kh_end(h))
+#define git_oidmap_has_data(h, idx) kh_exist(h, idx)
 
 #define git_oidmap_value_at(h, idx) kh_val(h, idx)