Add ability to set DIB_IMAGE_SIZE parameter for CentOS images

Change-Id: Icdc8a92558fc5df84d040172ef97441db7942526
Partial-bug: #1304100
Fix install Oozie for vanilla 2 plugin

If you build all images for vanilla plugin then for vanilla 2
image install oozie with hadoop 1. This patch fixed it.

Closes-bug: #1305123

Change-Id: Ic9911b05774b063dc7640d8fdaa684fa7688ae71
Merge "Fix install Oozie for vanilla 2 plugin"
Merge "Add ability to set DIB_IMAGE_SIZE parameter for CentOS images"
Merge branch 'master' into exp-merge

Conflicts:
	diskimage-create/diskimage-create.sh
Update docs and commented code