devicemapper: define device-mapper log levels

Signed-off-by: Vincent Batts <vbatts@redhat.com>

pkg/devicemapper/log.go

@@ -0,0 +1,11 @@
+package devicemapper
+
+// definitions from lvm2 lib/log/log.h
+const (
+	LogLevelFatal  = 2 + iota // _LOG_FATAL
+	LogLevelErr               // _LOG_ERR
+	LogLevelWarn              // _LOG_WARN
+	LogLevelNotice            // _LOG_NOTICE
+	LogLevelInfo              // _LOG_INFO
+	LogLevelDebug             // _LOG_DEBUG
+)