Enforce the read call returns correct value
Enforce the read call returns correct value

fix compilation error on Ubuntu 12.0

In file included from /usr/include/fcntl.h:252:0,
                 from /home/ajg23/src/ceres-solver/examples/libmv_bundle_adjuster.cc:91:
/home/ajg23/src/ceres-solver/examples/libmv_bundle_adjuster.cc: In member function ‘T {anonymous}::EndianAwareFileReader::Read() const [with T = unsigned char]’:
/home/ajg23/src/ceres-solver/examples/libmv_bundle_adjuster.cc:300:5: error: ignoring return value of ‘ssize_t read(int, void*, size_t)’, declared with attribute warn_unused_result [-Werror=unused-result]

Change-Id: Ib23ca19778761bbfe0d77bcf32a2181ce6db1a12

jmwalls/ceres-solver-fork,entylop/ceres-solver,ikoruk/ceres-solver,timfel/ceres-bin,timfel/ceres-bin,DougFirErickson/ceres-solver,kartikkumar/ceres-solver,ysonggit/ceres-solver,ysonggit/ceres-solver,stonier/ceres_solver,jmwalls/ceres-solver-fork,ikoruk/ceres-solver,stonier/ceres_solver,ysonggit/ceres-solver,DougFirErickson/ceres-solver,jmwalls/ceres-solver-fork,whuaegeanse/ceres-solver,kartikkumar/ceres-solver,DougFirErickson/ceres-solver,kartikkumar/ceres-solver,timfel/ceres-bin,whuaegeanse/ceres-solver,entylop/ceres-solver,whuaegeanse/ceres-solver,stonier/ceres_solver,ysonggit/ceres-solver,timfel/ceres-bin,DougFirErickson/ceres-solver,whuaegeanse/ceres-solver,entylop/ceres-solver,kartikkumar/ceres-solver,ikoruk/ceres-solver,ikoruk/ceres-solver,stonier/ceres_solver,entylop/ceres-solver,ikoruk/ceres-solver,jmwalls/ceres-solver-fork