Clear clipboard once we're done with the drag
Clear clipboard once we're done with the drag

jclive pointed out that not doing so is a security, e.g.,
an entry's password is in the paste buffer, which the user
might not expect, and has no easy way to clear.

ronys/pwsafe-test,gpmidi/pwsafe,Sp1l/pwsafe,gpmidi/pwsafe,Sp1l/pwsafe,ronys/pwsafe-test,sorinAche23/Psafe,Sp1l/pwsafe,ronys/pwsafe-test,ronys/pwsafe-test,gpmidi/pwsafe,gpmidi/pwsafe,ronys/pwsafe-test,ronys/pwsafe-test,gpmidi/pwsafe,sorinAche23/Psafe,ronys/pwsafe-test,sorinAche23/Psafe,gpmidi/pwsafe,Sp1l/pwsafe,ronys/pwsafe-test,sorinAche23/Psafe,Sp1l/pwsafe,Sp1l/pwsafe,sorinAche23/Psafe,sorinAche23/Psafe,sorinAche23/Psafe,gpmidi/pwsafe,Sp1l/pwsafe,gpmidi/pwsafe,Sp1l/pwsafe,sorinAche23/Psafe