Fix gzip header for compressed files during log file rotation

An error in the gzip header (during log file rotation) resulted in
the linux "file" command thinking the original name of log files were
file.log.1.gz rather than file.log. This caused problems on Windows
with some of the GUI tools.

Fixes issue #26

rotatelogs.go

@@ -85,7 +85,7 @@ func compressLogFile(logFileRoot string) error {
 	defer writer.Close()
 
 	archiver := gzip.NewWriter(writer)
-	archiver.Name = logFileRoot + ".1.gz"
+	archiver.Name = logFileRoot
 	defer archiver.Close()
 
 	if _, err := io.Copy(archiver, reader); err != nil {