Fix warnings which accidentally got into master

[Arturs Bekasovs]

They were introduced as a part of #6980 and I've not noticed them before closing the ticket:

[..]/Graph.cpp: In member function ‘void Graph::guessUniqueCurveLayout(int&, int&)’:
[..]/Graph.cpp:5030:64: warning: operation on ‘colorIndex’ may be undefined [-Wsequence-point]
[..]/Graph.cpp:5034:35: warning: operation on ‘symbolIndex’ may be undefined [-Wsequence-point]

[Arturs Bekasovs]

Refs #8234. Replaced increments with a simple plus operations.

Changeset: 367e1bb5f614e86047b72658140740a04f644313

[Arturs Bekasovs]

Tester:

Make sure warnings were resolved. Verify that what I've done shouldn't affect the way the code works.

I've checked the build server results, and it seems that Ubuntu 12.04 is only one which was noticing these problems. You can see them at ​http://download.mantidproject.org/jenkins/view/Develop%20Clean%20Builds%20and%20Tests/job/is_clean_ubuntu-12.04_develop/237/warnings20Result

To be 100% it's all OK and I've not broken #6980, please check the following:

1. Plot some spectra of any data file.
2. Set the color of the last spectra to pink.
3. Add more spectra, and make sure they all get different colors, in the same order colors appear in the ColorBox. The white color should be skipped.

[Russell Taylor]

Merge remote branch 'origin/feature/8234_sequence_point_warnings'

Full changeset: ​19937a7ad44c15e634eacddf30a533d35ce4caaa

[Russell Taylor]

The warnings are gone, and I've learnt something new. The problem was that the colorIndex (or symbolIndex) variable was being assigned a new value twice in the expression - once via operator++ and once in the assignment. I thought using operator++ looked more concise and was fine, since the RHS has to be evaluated before being assigned to the LHS. But it turns out that the timing/order of the stores to colorIndex is not guaranteed - hence the warning. Of course, colorIndex+1 only reads from the variable so it's fine.

[Arturs Bekasovs]

Deleted

[Stuart Campbell]

This ticket has been transferred to github issue ​9079