qa/suites/rados/singleton-nomsgr: fix syntax

This parsed out as

  tasks:
  - install: null
  - ceph:
      conf:
        osd: osd max object name len = 400 osd max object namespace len = 64
  - workunit:
      clients:
        all:
        - rados/test_health_warnings.sh

which is clearly not correct.

Signed-off-by: Sage Weil <sage@redhat.com>

qa/suites/rados/singleton-nomsgr/all/health-warnings.yaml

@@ -6,8 +6,8 @@ tasks:
     conf:
       osd:
 # we may land on ext4
-        osd max object name len = 400
-        osd max object namespace len = 64
+        osd max object name len: 400
+        osd max object namespace len: 64
 - workunit:
     clients:
       all: