util/patternMatch: don't extract a QCString(QFileInfo) each time we QRegExp.match

patternMatch iterates over the pattern list, while FileInfo remains
constant.

given this, extract the QCStrings for QFileInfo outside of the
iterating loop.

Signed-off-by: Adrian Negreanu <adrian.m.negreanu@intel.com>
Merge pull request #129 from groleo/master

util/patternMatch: don't extract a QCString(QFileInfo) each time we QReg...