PR #9304 added support for functions in clipboard providers. As part of
the PR I meant to move two checks in the provider code out of an if
statement into separate statements and adding additional checks for
g:clipboard attributes - as it turns out the code is wrong and it does
not implement additional checks while it adds two conditions that make
very little sense
type(g:clipboard['copy']) #isnot# v:t_func
what would make sense would be something along the lines of
type(g:clipboard['copy']['+']) #isnot# v:t_func
but might not be what we want either, so I'm reverting this.
d207440f1e
