Updating an indexed attribute

[Hilaire Fernandes]

While using noteOldKeyFor:, I noted that using this method and changing 
the attribute out of a commit block (and doing a commit: [] latter) 
makes the modified attribute not always re-indexed.

When working with Integer attribute (using the MaIntegerIndex), it is ok 
to do as above. When using my own MaCompetencyIndex it does not work

I guess it is not the right way to do it that way. So better be careful 
to not be too laszy with the commit:[]. I was tempted to do a batch of 
changes then conmiting later.

Hilaire