Fixed the potential error reported by Prefast code analysis

[yitam]

To fix this warning from Prefast:
pdo_sqlsrv\pdo_dbh.cpp(1303) : warning C6385: Reading invalid data from 'last_insert_id_query': the readable size is '184' bytes, but '2147483647' bytes may be read.

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This change is 

[codecov-io]

Codecov Report

Merging #788 into dev will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##              dev     #788   +/-   ##
=======================================
  Coverage   80.06%   80.06%           
=======================================
  Files          25       25           
  Lines        7323     7323           
=======================================
  Hits         5863     5863           
  Misses       1460     1460

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[david-puglielli]

Isn't it possible that any call to strlen_s would produce this error, since we don't specify the length argument?

[yitam]

@david-puglielli -- in this particular case strnlen_s() was called to determine how many characters are in the input string to be converted. Yet, it should never reach INT_MAX (2147483647), the limit that we use for strnlen_s() , because last_insert_id_query is either LAST_INSERT_ID_QUERY or SEQUENCE_CURRENT_VALUE_QUERY with the sequence name. However, the code change in this PR is required to get rid of this warning.

[coveralls]

Coverage increased (+0.003%) to 74.7% when pulling 10ff344 on yitam:fillLastID into 4509756 on Microsoft:dev.