convert-zipmap-hash-on-load false positive fixed.

Apparently because the sample RDB file was not copied before every test
Redis had a chance to replace it with a newly written one, so that the
next test could fail.

tests/integration/convert-zipmap-hash-on-load.tcl

-set server_path [tmpdir "server.convert-zipmap-hash-on-load"]
-
 # Copy RDB with zipmap encoded hash to server path
-exec cp tests/assets/hash-zipmap.rdb $server_path
+set server_path [tmpdir "server.convert-zipmap-hash-on-load"]
 
+exec cp -f tests/assets/hash-zipmap.rdb $server_path
 start_server [list overrides [list "dir" $server_path "dbfilename" "hash-zipmap.rdb"]] {
   test "RDB load zipmap hash: converts to ziplist" {
     r select 0
@@ -13,6 +12,7 @@ start_server [list overrides [list "dir" $server_path "dbfilename" "hash-zipmap.
   }
 }
 
+exec cp -f tests/assets/hash-zipmap.rdb $server_path
 start_server [list overrides [list "dir" $server_path "dbfilename" "hash-zipmap.rdb" "hash-max-ziplist-entries" 1]] {
   test "RDB load zipmap hash: converts to hash table when hash-max-ziplist-entries is exceeded" {
     r select 0
@@ -23,6 +23,7 @@ start_server [list overrides [list "dir" $server_path "dbfilename" "hash-zipmap.
   }
 }
 
+exec cp -f tests/assets/hash-zipmap.rdb $server_path
 start_server [list overrides [list "dir" $server_path "dbfilename" "hash-zipmap.rdb" "hash-max-ziplist-value" 1]] {
   test "RDB load zipmap hash: converts to hash table when hash-max-ziplist-value is exceeded" {
     r select 0