added CentOS 6-specific instructions to the HOWTO. (#4157)
added CentOS 6-specific instructions to the HOWTO. (#4157)

JayanthyChengan/dataverse,JayanthyChengan/dataverse,JayanthyChengan/dataverse,JayanthyChengan/dataverse,JayanthyChengan/dataverse,JayanthyChengan/dataverse,JayanthyChengan/dataverse,JayanthyChengan/dataverse