esx: avoid dead code

esx: avoid dead code

Detected by Coverity.  The beginning of the function already filtered
out NULL objectContentList as invalid.  Further investigation shows:

esxVI_RetrieveProperties is generated and returns a list of objects
that match the given propertyFilterSpec.
esxVI_LookupObjectContentByType then tests whether the result
corresponds to the expected occurrence and reports an error otherwise.
This simplifies the callers of  esxVI_LookupObjectContentByType, but
due to the missing dereference the check was never performed because
the code thought that at least one item was obtained. NULL represents
an empty list. This is a potential segfault fix because callers of
esxVI_LookupObjectContentByType that specified "required" occurrence
assume *objectContentList to be non-NULL when
esxVI_LookupObjectContentByType succeeds.

* src/esx/esx_vi.c (esxVI_LookupObjectContentByType): Check
correct pointer.