Memory deallocation error in _qf_multi_merge

[fazalmajid]

ASAN flagged an error, inverted_indexes in _qf_multi_merge is allocated using new[] but deallocated using delete instead of delete[]. This diff fixes this:

diff --git a/third-party/MQF/src/gqf.cpp b/third-party/MQF/src/gqf.cpp
--- a/third-party/MQF/src/gqf.cpp
+++ b/third-party/MQF/src/gqf.cpp
@@ -2883,7 +2883,7 @@
                smallest_key=second_smallest_key;
        }
        // cout<<"before delete"<<endl;
-       delete  inverted_indexes;
+       delete[]  inverted_indexes;
        for(i=0;i<nqf;i++)
        {
                delete qfi_arr[I];