pgm-daemon.txt: Remove description of slave setup
pgm-daemon.txt: Remove description of slave setup

SiteProgram.java is not capable of setting sitePath to null, therefore
startup configuration is only read from gerrit.config. It's still
possible to specify configuration via system property when running from
a servlet container, but that's not the daemon program.

Change-Id: I3210e4999051173713eb04728806cfcb22ace7ca

qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit