git config core.ignorecase).
One way of making Git recognize the change is moving the contents of the directory to another, remove it or just change the capitalization, commit the change, create again the original one with the new name if you deleted it, move back the files to it and amend the previous commit, as in the following example:
> mkdir temp > mv Original/* temp > rm -d Original > git add . > git commit -am "Renamed directories" > mkdir original > mv temp/* original > git add . > git commit --amend --no-edit
A simpler way of doing it is using
git mv -f Original/* original
It can also be done by changing the ignorecase value for the project:
git config core.ignorecase false