[INTERNAL/REFACTOR] put SAROS constant variable back to Saros/E

The value described by this value is Eclipse specific and should not be
in another context (e.g other Saros IDE plugins)

Change-Id: I50241cf874a2179848ef1b23a5066786699d1a03
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1958
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>
Reviewed-by: Holger Schmeisky <google@schmeisky.com>