[Toaster] [review-request] fix banner after customimage package add

[Dave Lerner]

Branch: toaster-next
Defect: 9101
Summary: toaster: fix banner after customimage package add

Test Setup
----------
Build core-image-sato in order to capture package dependencies for tests.
Create a new custom image based on core-image-minimal.
Test with the pacakge atk which has 3 unadded dependencies: libpcre, glib-2.0, and libffi.
Make certain that old orm_customimage_* tables are empty, no residuals from 
priof runs.

Test cases and expected results
-------------------------------
Verify that adding a package with unaddded dependencies will add the dependencies visually and in the build by:
    Click the 'add package' button for package atk.
    Click 'add package' in the popup modal dialog to add the 3 dependencies.
    Verify that all 4 packages, atk and 3 dependents, now show buttons with
        labels 'remove package' instead of 'add...'
    Build the image.
    Verify in the built image under packages that all 4 packages are added
        to the image using the right panel Packages and clicking each package.

Verify that adding a package with either 
- dependencies already added or in the base image, 
- witout dependencies 
correctly shows the addition of 1 package in the banner.
    Remove atk, then add it back atk. 
    Verify that banner says 
        "You have added <bold>1</bold> package to myimage : atk"
    Note: only 1 package because dependencies were not removed in previous
        step. 

Verify removing the 'added' package and each of the dependencies removes those
    packages visually and in the build.
    Click 'remove package' for packages and in order: 
        atk, glib-2.0, libffi, libpcre.
    Build the image.
    Verify that the packages are not in the image.

Verify fix of the defect symptom that adding dependent package, then removing
    dependent package and dependencies, then adding it back correctly
    shows the dependencies as added, ie, with "remove package" button.