why there are two ssl_certs folders in Centos

/usr/local/lib/ruby/2.1.0/rubygems/ssl_certs

/usr/local/lib/ruby/site_ruby/2.1.0/rubygems/ssl_certs

The contents are different as well.

The first one has the following .pem:

Class3PublicPrimaryCertificationAuthority.pem
DigiCertHighAssuranceEVRootCA.pem        
EntrustnetSecureServerCertificationAuthority.pem
GeoTrustGlobalCA.pem

The second one has the following .pem:

AddTrustExternalCARoot-2048.pem
AddTrustExternalCARoot.pem
Class3PublicPrimaryCertificationAuthority.pem
DigiCertHighAssuranceEVRootCA.pem
EntrustnetSecureServerCertificationAuthority.pem
GeoTrustGlobalCA.pem