Fix missing function declarations for pread and close
Fix missing function declarations for pread and close

sparsebundlefs.cpp:171:56: error: 'pread' was not declared in this scope
sparsebundlefs.cpp:172:24: error: 'close' was not declared in this scope

We were missing unistd.h

torarnv/sparsebundlefs,torarnv/sparsebundlefs