Update COPYREC to use -R (Fix #784)
Update COPYREC to use -R (Fix #784)

`-R` copy symbolic links while `-r` follow link and then copy the file

or-tools/or-tools,or-tools/or-tools,google/or-tools,google/or-tools,or-tools/or-tools,google/or-tools,google/or-tools,or-tools/or-tools,google/or-tools,or-tools/or-tools,or-tools/or-tools,google/or-tools