Fixed issue 04688: Invalid values in single select question statistics causing Warning: imagefilledpolygon() warning when creating graphs
Dev The 'Other' field is now emptied if a value other than '-oth-' was set for the main field (prevents other values being saved - for example if Javascript fails to hide the 'Other' input field). I also patched statistics to handle this correctly by not counting the number of 'Other' entries but by counting the number of '-oth-' entries in the main field.

git-svn-id: file:///Users/Shitiz/Downloads/lssvn/source/limesurvey@9349 b72ed6b6-b9f8-46b5-92b4-906544132732