tests/dashboard: use the dedicated grafana node

The Vagrant dashboard scenario creates a dedicated grafana node but
was not use in the ansible inventory.
Signed-off-by: Dimitri Savineau <dsavinea@redhat.com>
(cherry picked from commit a9a1f633)

tests/functional/dashboard/container/hosts

@@ -9,4 +9,4 @@ osd0
 osd1
 
 [grafana-server]
-mon0
\ No newline at end of file
+grafana0
\ No newline at end of file

tests/functional/dashboard/container/hosts-ubuntu

@@ -9,7 +9,7 @@ osd0
 osd1
 
 [grafana-server]
-mon0
+grafana0
 
 [all:vars]
 debian_ceph_packages=['ceph', 'ceph-common', 'ceph-fuse']

tests/functional/dashboard/hosts

@@ -9,4 +9,4 @@ osd0
 osd1
 
 [grafana-server]
-mon0
\ No newline at end of file
+grafana0
\ No newline at end of file

tests/functional/dashboard/hosts-ubuntu

@@ -9,7 +9,7 @@ osd0
 osd1
 
 [grafana-server]
-mon0
+grafana0
 
 [all:vars]
 debian_ceph_packages=['ceph', 'ceph-common', 'ceph-fuse']