scm: git: use "-c log.decorate=no" option instead of "--no-decorate" of "git log" above Git 1.7.2 (#8081, #8083).
Git on Redmine CI Server does not support "--no-decorate" option of "git log".
Authored by: tmaruyama 2011-04-06
Parent: [r5348]
Child: [r5350]
