Remove eof flag

eof flag added at this commit (https://github.com/Polymer/vulcanize/commit/4fa2b9e6b69afcaa1c970ee8ded2b4c3d19be08f#diff-2fd25663c1d3dca2153ce60dac0f7245R272) eof flag should be used in last writingFileSync. eof mean is that a file is the last file wrting.