r1277: don't apply rescored filtering with -P

Since v2.19-ish, minimap2 rescores base alignment based on the best alignment
of a read. This heuristic sometimes improve the mapping accuracy of the best
alignment but may too aggressively filter weaker hits.

Resolve #969

minimap.h

@@ -5,7 +5,7 @@
 #include <stdio.h>
 #include <sys/types.h>
 
-#define MM_VERSION "2.28-r1276-dirty"
+#define MM_VERSION "2.28-r1277-dirty"
 
 #define MM_F_NO_DIAG       (0x001LL) // no exact diagonal hit
 #define MM_F_NO_DUAL       (0x002LL) // skip pairs where query name is lexicographically larger than target name