Description of problem:
The InstallMode of the descheduler operator is "AllNamespaces", but it doesn't support watching all namespaces.

Version-Release number of selected component (if applicable):
Current version: 4.0.0-0.nightly-2019-03-13-233958

How reproducible:
always

Steps to Reproduce:
1. Install the OCP 4.0 via the installer.
2. Install the Descheduler Operator on the Web console. It will be installed in the "openshift-operators" project.
3. Create a descheduler resource in another project called "test", like below:
apiVersion: descheduler.io/v1alpha1
kind: Descheduler
metadata:
  name: example-2
  namespace: test
spec:
  schedule: "*/1 * * * ?"       
  strategies: 
    - name: "lownodeutilization"
      params:
       - name: "cputhreshold"
         value: "10"
       - name: "memorythreshold"
         value: "20"
       - name: "memorytargetthreshold"
         value: "30"

Actual results:
Only the Descheduler kind generated, no corresponding resource generated.
[jzhang@dhcp-140-18 ocp14]$ oc get pods -n test
No resources found.
[jzhang@dhcp-140-18 ocp14]$ oc get descheduler -n test
NAME        AGE
example     77m
[jzhang@dhcp-140-18 ocp14]$ oc get descheduler -n test example-2 -o yaml
apiVersion: descheduler.io/v1alpha1
kind: Descheduler
metadata:
  creationTimestamp: 2019-03-14T06:23:31Z
  generation: 1
  name: example-2
  namespace: test
  resourceVersion: "109848"
  selfLink: /apis/descheduler.io/v1alpha1/namespaces/test/deschedulers/example-2
  uid: b0223e30-4621-11e9-8f2d-0a82fa5c54fe
spec:
  schedule: '*/1 * * * ?'
  strategies:
  - name: lownodeutilization
    params:
    - name: cputhreshold
      value: "10"
    - name: memorythreshold
      value: "20"
    - name: memorytargetthreshold
      value: "30"


Expected results:
The descheduler resource should be generated successfully. Because its csv support watching all namespaces.
[jzhang@dhcp-140-18 ocp14]$ oc get csv descheduler.v0.0.1 -o yaml |grep -i installmode -A 9
  installModes:
  - supported: true
    type: OwnNamespace
  - supported: true
    type: SingleNamespace
  - supported: false
    type: MultiNamespace
  - supported: true
    type: AllNamespaces

Additional info:
If created the descheduler resource in the same project as the descheduler operator, it works well.