Don't crash when we see too many O2 sensors

I can think of very, very, VERY few circumstances where it makes sense to crash
an end user application. This isn't one of them.

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

core/profile.c

@@ -6,7 +6,6 @@
 #include "gettext.h"
 #include <limits.h>
 #include <string.h>
-#include <assert.h>
 #include <stdlib.h>
 
 #include "dive.h"
@@ -1156,7 +1155,8 @@ static int calculate_ccr_po2(struct plot_data *entry, const struct divecomputer
 				return sump / 3;
 		}
 	default: // This should not happen
-		assert(np <= 3);
+		// assert(np <= 3);
+		printf("calculate_ccr_po2: np > 3 -- that's a problem, but maybe not enough to crash the app\n");
 		return 0;
 	}
 }