Improve handling for old XML files in Uemis downloader

In order to work in the most expected ways for people who have used
a version of Subsurface that didn't store the deviceid in the divecomputer
we relax the testing for when a divecomputer entry is assumed to match the
current divecomputer.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

uemis-downloader.c

@@ -735,7 +735,8 @@ static char *get_divenr(char *deviceidstr)
 		struct divecomputer *dc = &dive_table.dives[i]->dc;
 		while (dc) {
 			if (dc->model && !strcmp(dc->model, "Uemis Zurich") &&
-			    dc->deviceid == deviceid && dc->diveid > maxdiveid)
+			    (dc->deviceid == 0 || dc->deviceid == 0x7fffffff || dc->deviceid == deviceid) &&
+			    dc->diveid > maxdiveid)
 				maxdiveid = dc->diveid;
 			dc = dc->next;
 		}