UI: Use binary mode for QuickReadFile

When not using binary mode (i.e. text mode) CRLF will be converted to
LF, which means that the size provided by tellg() is no longer correct,
and reading prematurely hits an EOF and sets the fail bit.

UI/update/shared-update.cpp

@@ -68,7 +68,7 @@ try {
 
 static bool QuickReadFile(const char *file, std::string &data)
 try {
-	std::ifstream fileStream(file);
+	std::ifstream fileStream(file, std::ifstream::binary);
 	if (!fileStream.is_open() || fileStream.fail())
 		throw strprintf("Failed to open file '%s': %s", file,
 				strerror(errno));