unit_test.c: fix printf, remove unused parameter

Fix for:
[test/unit_test.c:827]: (warning) printf format string requires 0
 parameters but 1 is given.
[test/unit_test.c:833]: (warning) printf format string requires 0
 parameters but 1 is given.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>

test/unit_test.c

@@ -865,13 +865,13 @@ int __cdecl main(void) {
     if (f) {
         fclose(f);
     } else {
-        printf("Error: Test directory does not contain hello.txt\n", buffer);
+        printf("Error: Test directory does not contain hello.txt\n");
     }
     f = fopen("unit_test.c", "r");
     if (f) {
         fclose(f);
     } else {
-        printf("Error: Test directory does not contain unit_test.c\n", buffer);
+        printf("Error: Test directory does not contain unit_test.c\n");
     }
 
     /* test local functions */