Add error message for a maintenance info conflict where info is nil in catalog
Add error message for a maintenance info conflict where info is nil in catalog

[#161178125]

Signed-off-by: Winna Bridgewater <8478e8b4d1baaa640a09edb56939e3354ff87a71@pivotal.io>
Co-authored-by: Winna Bridgewater <8478e8b4d1baaa640a09edb56939e3354ff87a71@pivotal.io>

pivotal-cf/brokerapi,pivotal-cf/brokerapi