Add argument checks to camel-block-file.c.
Add argument checks to camel-block-file.c.

matzipan/evolution-data-server,Distrotech/evolution-data-server,tintou/evolution-data-server,Distrotech/evolution-data-server,matzipan/evolution-data-server,Distrotech/evolution-data-server,Distrotech/evolution-data-server,gcampax/evolution-data-server,gcampax/evolution-data-server,tintou/evolution-data-server,Distrotech/evolution-data-server,tintou/evolution-data-server,tintou/evolution-data-server,matzipan/evolution-data-server,gcampax/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,gcampax/evolution-data-server