fix storage profile ems foreign key

[kbrock]

got the error that there is no ext_management_system_id
which is valid.

All other belongs_to :ext_management_system declarations also include
the foreign key

This caused an error when assigning an ems to a storage profile

[miq-bot]

Checked commit kbrock@4cdcf40 with ruby 2.5.7, rubocop 0.69.0, haml-lint 0.28.0, and yamllint
1 file checked, 1 offense detected

app/models/storage_profile.rb

• ❗ - Line 2, Col 3 - Rails/InverseOf - Specify an :inverse_of option.

[jrafanie]

@miq-bot add_label jansa/yes?

[simaishi]

Jansa backport details:

$ git log -1
commit 58a2fbc2f44fc752f5d7efcf8132ae93621254b5
Author: Adam Grare <agrare@redhat.com>
Date:   Wed Apr 1 18:43:21 2020 -0400

    Merge pull request #20038 from kbrock/storage_profile_ems

    fix storage profile ems foreign key

    (cherry picked from commit a0fe4caeab04e1f3d32ad1f5da82e84a50997584)