Removed unused variables

tests/diff/binary.c

@@ -277,7 +277,6 @@ void test_diff_binary__empty_for_no_diff(void)
 	git_tree *tree;
 	git_diff *diff;
 	git_buf actual = GIT_BUF_INIT;
-	const char *expected = "";
 
 	opts.flags = GIT_DIFF_SHOW_BINARY | GIT_DIFF_FORCE_BINARY;
 	opts.id_abbrev = GIT_OID_HEXSZ;

tests/diff/workdir.c

@@ -1791,7 +1791,6 @@ void test_diff_workdir__only_writes_index_when_necessary(void)
 	git_index *index;
 	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff *diff = NULL;
-	git_diff_perfdata perf = GIT_DIFF_PERFDATA_INIT;
 	git_reference *head;
 	git_object *head_object;
 	git_oid initial, first, second;