Fix fencepost error detected by Coverity...

Because the test to continue is *after* the loop, we can't continue
when c is the last index into lzh->son, or the code will make use of
lzh->son[sizeof(lzh->son)/sizeof(lzh->son[0])] which is outside the bounds
of the array.

src/encode/lzh.c

@@ -468,7 +468,7 @@ static void lzh_update(lzh_t* lzh, short int c)
 
 			c = l;
 		}
-	} while (((c = lzh->prnt[c]) != 0) && c < (sizeof(lzh->son)/sizeof(lzh->son[0])));	/* do it until reaching the root */
+	} while (((c = lzh->prnt[c]) != 0) && c < ((sizeof(lzh->son)/sizeof(lzh->son[0]))-1));	/* do it until reaching the root */
 }
 
 static void lzh_encode_char(lzh_t* lzh, unsigned short c, uint8_t *outbuf, int32_t *outlen)