fix a couple of issues found with llvm-analyze

src/shared/logs-show.c

@@ -273,6 +273,7 @@ finish:
         free(message);
         free(monotonic);
         free(realtime);
+        free(priority);
 
         return r;
 }

src/shared/utf8.c

@@ -275,7 +275,7 @@ char *ascii_filter(const char *str) {
         if (!r)
                 return NULL;
 
-        for (s = r, d = r; *s; s++)
+        for (s = str, d = r; *s; s++)
                 if ((unsigned char) *s < 128)
                         *(d++) = *s;