Patch from Greg Burd: Improve portability of the build-apidoc.sh script by replacing readlink
Patch from Greg Burd: Improve portability of the build-apidoc.sh script by replacing readlink

Review: https://reviews.apache.org/r/6733/

Testing: Applied patch, and ran 'ant clean-all build-apidocs'
on both OSX and Ubuntu 12. Initial testing confirmed the issue
that Greg discovered on OSX.  After the patch, the docs built
correctly.

GabrielBrascher/cloudstack,resmo/cloudstack,GabrielBrascher/cloudstack,mufaddalq/cloudstack-datera-driver,DaanHoogland/cloudstack,wido/cloudstack,resmo/cloudstack,DaanHoogland/cloudstack,mufaddalq/cloudstack-datera-driver,DaanHoogland/cloudstack,GabrielBrascher/cloudstack,resmo/cloudstack,resmo/cloudstack,wido/cloudstack,GabrielBrascher/cloudstack,DaanHoogland/cloudstack,wido/cloudstack,mufaddalq/cloudstack-datera-driver,DaanHoogland/cloudstack,GabrielBrascher/cloudstack,jcshen007/cloudstack,GabrielBrascher/cloudstack,resmo/cloudstack,mufaddalq/cloudstack-datera-driver,resmo/cloudstack,wido/cloudstack,wido/cloudstack,jcshen007/cloudstack,mufaddalq/cloudstack-datera-driver,DaanHoogland/cloudstack,GabrielBrascher/cloudstack,mufaddalq/cloudstack-datera-driver,jcshen007/cloudstack,resmo/cloudstack,jcshen007/cloudstack,wido/cloudstack,jcshen007/cloudstack,DaanHoogland/cloudstack,wido/cloudstack,jcshen007/cloudstack,jcshen007/cloudstack