Code cleanup


DirectoryServer.java:
Changed getAttributeType(String lowerName, boolean returnDefault) to getAttributeTypeOrDefault(String lowerName).
Renamed getAttributeType(String lowerName, String upperName) to getAttributeTypeOrDefault(String lowerName, String upperName).

DirectoryConfig.java:
Removed getAttributeType(String lowerName, boolean returnDefault), used DirectoryServer methods instead.

*.java:
Changed all code that was calling DirectoryServer.getAttributeType(lowerName, false) to directly call the more explicit DirectoryServer.getAttributeType(lowerName).

SubjectAttributeToUserAttributeCertificateMapper.java:
In initializeCertificateMapper(), isConfigurationChangeAcceptable() and applyConfigurationChange(), extracted methods buildAttributeMap() and getUserBaseDNs() to remove code duplication