Update scratch_impl.h patch file

To mirror recent changes to the `scratch_impl.h` file update the patch
file.

Author: tcharding

secp256k1-sys/depend/scratch_impl.h.patch

@@ -14,11 +14,11 @@
 < 
 < static void secp256k1_scratch_destroy(const secp256k1_callback* error_callback, secp256k1_scratch* scratch) {
 <     if (scratch != NULL) {
-<         VERIFY_CHECK(scratch->alloc_size == 0); /* all checkpoints should be applied */
 <         if (secp256k1_memcmp_var(scratch->magic, "scratch", 8) != 0) {
 <             secp256k1_callback_call(error_callback, "invalid scratch space");
 <             return;
 <         }
+<         VERIFY_CHECK(scratch->alloc_size == 0); /* all checkpoints should be applied */
 <         memset(scratch->magic, 0, sizeof(scratch->magic));
 <         free(scratch);
 <     }