libxc: initalize stdio loggers' progress_last_percent values to 0

...otherwise they are undefined in the first progress callback.

Coverity-ID: 1056055
Signed-off-by: Matthew Daley <mattjd@gmail.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

tools/libxc/xtl_logger_stdio.c

@@ -172,6 +172,7 @@ xentoollog_logger_stdiostream *xtl_createlogger_stdiostream
     if (newlogger.flags & XTL_STDIOSTREAM_SHOW_DATE) tzset();
 
     newlogger.progress_erase_len = 0;
+    newlogger.progress_last_percent = 0;
 
     return XTL_NEW_LOGGER(stdiostream, newlogger);
 }