regression: performance problem with qlonglong due to treating qlongloang as SQLCS_NCHAR

This change http://qt.gitorious.org/qt/qt/commit/f8f255553f3640355d3e196e100778256741701c
caused the qlonglong processing performance dropped very much because of the following line in QTDIR\src\sql\drivers\oci\qsql_oci.cpp changed from
static const ub1 qOraCharsetForm = SQLCS_IMPLICIT;

to
static const ub1 qOraCharsetForm = SQLCS_NCHAR;