Merge "Don't wipe power stats data storage on a reboot."

            // filename, so any files that don't match the current version number can be deleted.

            File[] files = mDataStorageDir.listFiles();

            for (int i = 0; i < files.length; i++) {

                if (!files[i].getName().matches(dataStorageFilename + "(.*)")) {

                // Meter and model files are stored in the same directory.

                //

                // The format of filenames on disk is:

                //    log.powerstats.meter.version.timestamp

                //    log.powerstats.model.version.timestamp

                //

                // The format of dataStorageFilenames is:

                //    log.powerstats.meter.version

                //    log.powerstats.model.version

                //

                // A PowerStatsDataStorage object is created for meter and model data.  Strip off

                // the version and check that the current file we're checking starts with the stem

                // (log.powerstats.meter or log.powerstats.model). If the stem matches and the

                // version number is different, delete the old file.

                int versionDot = dataStorageFilename.lastIndexOf('.');

                String beforeVersionDot = dataStorageFilename.substring(0, versionDot);

                // Check that the stems match.

                if (files[i].getName().startsWith(beforeVersionDot)) {

                    // Check that the version number matches.  If not, delete the old file.

                    if (!files[i].getName().startsWith(dataStorageFilename)) {

                        files[i].delete();

                    }

                }

            }

            mFileRotator = new FileRotator(mDataStorageDir,

                                           dataStorageFilename,