Percolator: Fix handling of nested documents

[bly2k]

The percolator appears to have some strange matching behavior with nested objects defined in the document mapping. Steps to reproduce:

curl -XDELETE localhost:9200/test

curl -XPUT localhost:9200/test -d '{
"settings": {
"index.number_of_shards": 1,
"index.number_of_replicas": 0
},
"mappings": {
"doc": {
"properties": {
"persons": {
"type": "nested"
}
}
}
}
}'

curl -XPUT localhost:9200/test/.percolator/1 -d '{
"query": {
"bool": {
"must": {
"match": {
"name": "obama"
}
}
}
}
}'

curl -XPUT localhost:9200/test/.percolator/2 -d '{
"query": {
"bool": {
"must_not": {
"match": {
"name": "obama"
}
}
}
}
}'

curl -XPUT localhost:9200/test/.percolator/3 -d '{
"query": {
"bool": {
"must": {
"match": {
"persons.foo": "bar"
}
}
}
}
}'

curl -XPUT localhost:9200/test/.percolator/4 -d '{
"query": {
"bool": {
"must_not": {
"match": {
"persons.foo": "bar"
}
}
}
}
}'

curl -XPUT localhost:9200/test/.percolator/5 -d '{
"query": {
"bool": {
"must": {
"nested": {
"path": "persons",
"query": {
"match": {
"persons.foo": "bar"
}
}
}
}
}
}
}'

curl -XPUT localhost:9200/test/.percolator/6 -d '{
"query": {
"bool": {
"must_not": {
"nested": {
"path": "persons",
"query": {
"match": {
"persons.foo": "bar"
}
}
}
}
}
}
}'

curl -XPOST localhost:9200/_refresh

Thi should only match 1 and 5, but instead it matches 1,2,3,4,5,6

curl -XPOST localhost:9200/test/doc/_percolate?pretty -d '{
"doc": {
"name": "obama",
"persons": [
{
"foo": "bar"
}
]
}
}'