fix mic create image error issue

fix mic create image error issue
This issue happend if %prepackages %packages sections are both in ks files.

Refering the change in https://github.com/rpm-software-management/rpm/commit/51b306686c46dfa67f6f9d16f0190c99f55339dd
Initialize plugins much earlier, it is initialized in AddInstall funciton not run(),
Before in rpm 4.11, once ts_pre run(), it will re-initialize plugins.
But now for rpm 4.14, after ts_pre.run() finish, msm handler is freed, so in ts.run(), when checking msm
handler, because it is NULL, this error will come.
So should call ts.AddInstall() after ts_pre.run().

error: Device security policy is missing. Unable to proceed
error: Plugin msm: hook tsm_pre failed

Change-Id: Iddd7c3c1c942960724c554926c444720d067f0bb
Signed-off-by: biao716.wang <biao716.wang@samsung.com>