git: limit scope of `logp` alias display
git: limit scope of `logp` alias display

Don't display all commits. This is useful for the graph alias but can be
confusing for linear displays of commits. The `logp` alias will now only
show commits for the tree that is checked out.

Stubby/dotfiles,senorflor/linux-dotfiles,marc0uk/dotfiles,intiocean/dotfiles,senorflor/dotfiles,nick-thompson/dotfiles,micahwood/linux-dotfiles,micahwood/linux-dotfiles,lgaechter/dotfiles,pmacom/dotfiles,bronxct1/dotfiles,saclark/dotfiles,codfish/dotfiles,Stubby/dotfiles,jmyser/dotfiles,sdillingham/dotfiles,micahwood/linux-dotfiles,codfish/dotfiles,pertoyra/dotfiles,seiryu9/dotfiles,Gastove/dotfiles,micahwood/linux-dotfiles,bronxct1/dotfiles,SBoudrias/dotfiles,micahwood/linux-dotfiles,SiTaggart/dotfiles,seiryu9/dotfiles,necolas/dotfiles