Drop padding in blk* when finalizing file

src/util.cpp

@@ -1161,6 +1161,14 @@ int GetFilesize(FILE* file)
     return nFilesize;
 }
 
+bool TruncateFile(FILE *file, unsigned int length) {
+#if defined(WIN32)
+    return _chsize(_fileno(file), length) == 0;
+#else
+    return ftruncate(fileno(file), length) == 0;
+#endif
+}
+
 // this function tries to make a particular range of a file allocated (corresponding to disk space)
 // it is advisory, and the range specified in the arguments will never contain live data
 void AllocateFileRange(FILE *file, unsigned int offset, unsigned int length) {