win32: `remediation` not `cleanup`

The `remediation` function is run in the retry loop in order to attempt
to fix any problems that the prior run encountered.  There is nothing
"cleaned up".  Clarify the name.
diff --git a/src/win32/posix_w32.c b/src/win32/posix_w32.c
index c7094db..e4fe414 100644
--- a/src/win32/posix_w32.c
+++ b/src/win32/posix_w32.c
@@ -160,11 +160,11 @@
 		os_error == ERROR_ACCESS_DENIED);
 }
 
-#define do_with_retries(fn, cleanup) \
+#define do_with_retries(fn, remediation) \
 	do {                                                             \
 		int __tries, __ret;                                          \
 		for (__tries = 0; __tries < git_win32__retries; __tries++) { \
-			if (__tries && (__ret = (cleanup)) != 0)                 \
+			if (__tries && (__ret = (remediation)) != 0)             \
 				return __ret;                                        \
 			if ((__ret = (fn)) != GIT_RETRY)                         \
 				return __ret;                                        \