fix cut-and-paste error in verifier

Oops.
diff --git a/verifier.c b/verifier.c
index f2491a1..164fb4a 100644
--- a/verifier.c
+++ b/verifier.c
@@ -123,7 +123,7 @@
     int i;
     for (i = 4; i < eocd_size-3; ++i) {
         if (eocd[i  ] == 0x50 && eocd[i+1] == 0x4b &&
-            eocd[i+2] == 0x05 && eocd[i+1] == 0x06) {
+            eocd[i+2] == 0x05 && eocd[i+3] == 0x06) {
             // if the sequence $50 $4b $05 $06 appears anywhere after
             // the real one, minzip will find the later (wrong) one,
             // which could be exploitable.  Fail verification if