Fix typo in NuGet spec.
Fix typo in NuGet spec.

zaccharles/nodatime,malcolmr/nodatime,nodatime/nodatime,jskeet/nodatime,jskeet/nodatime,malcolmr/nodatime,zaccharles/nodatime,BenJenkinson/nodatime,malcolmr/nodatime,BenJenkinson/nodatime,nodatime/nodatime,zaccharles/nodatime,zaccharles/nodatime,malcolmr/nodatime,zaccharles/nodatime,zaccharles/nodatime