vm subp - relies on currentBlock

[kumavis]

tried to run eth_call but the currentBlock wasnt set yet

   [Error: TypeError: Cannot read property 'parentHash' of undefined
       at blockFromBlockData (/Users/kumavis/dev/web3-provider-engine/subproviders/vm.js:267:38)
       at VmSubprovider.runVm (/Users/kumavis/dev/web3-provider-engine/subproviders/vm.js:66:15)
       at VmSubprovider.handleRequest (/Users/kumavis/dev/web3-provider-engine/subproviders/vm.js:33:8)
       at next (/Users/kumavis/dev/web3-provider-engine/index.js:93:18)
       at FilterSubprovider.handleRequest (/Users/kumavis/dev/web3-provider-engine/subproviders/filters.js:76:7)
       at next (/Users/kumavis/dev/web3-provider-engine/index.js:93:18)
       at DefaultFixtures.FixtureProvider.handleRequest (/Users/kumavis/dev/web3-provider-engine/subproviders/fixture.js:25:5)
       at next (/Users/kumavis/dev/web3-provider-engine/index.js:93:18)
       at /Users/kumavis/dev/web3-provider-engine/subproviders/cache.js:98:5
       at BlockCacheStrategy.hitCheck (/Users/kumavis/dev/web3-provider-engine/subproviders/cache.js:211:12)],