Fix a resource leak (src/backend/utils/adt/rowtypes.c)

Hi.

Per Coverity.

The function *record_in* has a new report about resource leak.

I think Coverity is right.

The normal path of the function frees the memory of several variables used.
Therefore the failure path should also free them.
A quick search on the web shows several occurrences of "malformed record literal", therefore failure is common in this function.

Although Coveriy reports the leak of only buf.data, the variables *values* and *nulls* should also be released.

While there, move the creation of stringdata, to ensure that in case of failure, the buf.data variable is released correctly.

Attached a path.

best regards,

Ranier Vilela