Unpack JARs for running servers in $site_path/tmp

Instead of unpacking a running server into ~/.gerritcodereview/tmp
only use that location for commands like init where there is no active
site. From gerrit.sh always use $site_path/tmp for the JARs to isolate
servers that run on the same host under the same UNIX user account.

Change-Id: I688490ffbbf70312767bb766dc7ccbea52401ad1
2 files changed