Set noData_ to false while calling execute

fetch sets noData_ to true when OCIStmtFetch returns OCI_NO_DATA, so subsequent
calls to fetch returns ef_no_data immediately. But noData_ is not set to
false again anywhere other than the constructor.

noData_ should be set to false if OCIStmtExecute returns with success.
Merge branch 'develop' of https://github.com/faik/soci into faik-develop

Closes #173

[ci skip]