made static magic date readonly (code review #46)
made static magic date readonly (code review #46)

mtian/SiteExtensionGallery,kudustress/NuGetGallery2,KuduApps/NugetGallery16Fx45-DeleteMe,projectkudu/SiteExtensionGallery,ScottShingler/NuGetGallery,grenade/NuGetGallery_download-count-patch,kudustress/NuGetGallery2,mtian/SiteExtensionGallery,KuduApps/NuGetGallery,KuduApps/NuGetGallery,KuduApps/NuGetGallery,skbkontur/NuGetGallery,JetBrains/ReSharperGallery,KuduApps/NugetGallery16Fx45-DeleteMe,kudustress/NuGetGalleryOptmized,KuduApps/NuGetGallery,KuduApps/NuGetGallery,kudustress/NuGetGalleryOptmized,JetBrains/ReSharperGallery,kudustress/NuGetGallery,JetBrains/ReSharperGallery,KuduApps/NugetGallery21Fx45-DeleteMe,skbkontur/NuGetGallery,projectkudu/SiteExtensionGallery,KuduApps/NugetGallery21Fx45-DeleteMe,ScottShingler/NuGetGallery,grenade/NuGetGallery_download-count-patch,kudustress/NuGetGallery,ScottShingler/NuGetGallery,projectkudu/SiteExtensionGallery,skbkontur/NuGetGallery,grenade/NuGetGallery_download-count-patch,mtian/SiteExtensionGallery