odb: fix memory leaks due to not freeing hash context

src/odb.c

@@ -1373,6 +1373,8 @@ int git_odb_open_wstream(
 	(*stream)->received_bytes = 0;
 
 done:
+	if (error)
+		git__free(ctx);
 	return error;
 }
 

src/odb_loose.c

@@ -1030,6 +1030,7 @@ done:
 		git_futils_mmap_free(&stream->map);
 		git_zstream_free(&stream->zstream);
 		git_hash_ctx_cleanup(hash_ctx);
+		git__free(hash_ctx);
 		git__free(stream);
 	}