[labeling] allows data defined to align multiline when wordwrap function is used as expression (fix #11805)

Currently it is not possible to use data defined to align multiline text if wordwrap function is used for the label expression. This change allows to do it working. See: http://hub.qgis.org/issues/11805
Could probably just be:

```cpp
if ( !tmpLyr.wrapChar.isEmpty() || tmpLyr.getLabelExpression()->expression().contains( "wordwrap" ) )
```
It is easier to read and is [the same function underneath](https://qt.gitorious.org/qt/qt/source/61379d481a1a9d646c812df010089c6d52d18f31:src/corelib/tools/qstring.h#L900).

Note: please run `scripts/prepare-commit.sh` before submitting C++ code. It would have fixed up some of the spacing in your code. I recommend staging your changes before running the script, then you will see any diffs in your working tree (though there is also a diff saved by the script if anything is changed).