Simplify the way we set the default sh(1) PS1. No functional changes.

Reviewed by:	jilles
MFC after:	2 weeks
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D18662

share/skel/dot.shrc

@@ -33,11 +33,7 @@ alias g='egrep -i'
 
 
 # # set prompt: ``username@hostname$ '' 
-# PS1="`whoami`@`hostname | sed 's/\..*//'`"
-# case `id -u` in
-# 	0) PS1="${PS1}# ";;
-# 	*) PS1="${PS1}$ ";;
-# esac
+# PS1="`whoami`@\h\\$ "
 
 # search path for cd(1)
 # CDPATH=:$HOME