expat: remove no_static variant

[ryandesign (Ryan Carsten Schmidt)]

expat has a variant called no_static which disables the building of the static library. No other ports have a variant by this name. MacPorts policy is to build static and dynamic libraries for all ports whenever possible. expat's no_static variant was created in r10738. Previously the port always disabled the static library. Now it's just a variant, but there's no reason to have it since the static library doesn't take appreciably longer to build and it's small. Having fewer variants is better so the variant should be deleted.

[ryandesign (Ryan Carsten Schmidt)]

Deleted variant in r49541.

[(none)]

Milestone Port Enhancements deleted