lib: Fix compiler error on Windows

svn path=/trunk/boinc/; revision=18324

checkin_notes

@@ -5165,3 +5165,9 @@ Charlie 5 June 2009
 
     lib/
         filesys.cpp
+
+Charlie 8 June 2009
+    - lib: Fix compiler error on Windows.
+
+    lib/
+        filesys.cpp

lib/filesys.cpp

@@ -687,10 +687,10 @@ int FILE_LOCK::unlock(const char* filename) {
     if (close(fd)) {
         retval = -1;
     }
+    fd = -1;
 #endif
     boinc_delete_file(filename);
     locked = false;
-    fd = -1;
     return 0;
 }