libxl: Compile regular expression where it is used
libxl: Compile regular expression where it is used

The regular expression used to determine guest capabilities
was compiled in libxlCapsInitHost() but used in libxlCapsInitGuests().
Move compilation to libxlCapsInitGuests() where it is used, and free
the compiled regex after use.  Ensure not to free the regex if
compilation fails.

andreabolognani/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,agx/libvirt,taget/libvirt,crobinso/libvirt,elmarco/libvirt,libvirt/libvirt,shugaoye/libvirt,agx/libvirt,olafhering/libvirt,rlaager/libvirt,eskultety/libvirt,olafhering/libvirt,datto/libvirt,taget/libvirt,zhlcindy/libvirt-1.1.4-maintain,taget/libvirt,nertpinx/libvirt,shugaoye/libvirt,jardasgit/libvirt,libvirt/libvirt,datto/libvirt,zippy2/libvirt,elmarco/libvirt,shugaoye/libvirt,zippy2/libvirt,zhlcindy/libvirt-1.1.4-maintain,fabianfreyer/libvirt,crobinso/libvirt,agx/libvirt,elmarco/libvirt,cbosdo/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,datto/libvirt,datto/libvirt,agx/libvirt,cbosdo/libvirt,andreabolognani/libvirt,zhlcindy/libvirt-1.1.4-maintain,VenkatDatta/libvirt,datto/libvirt,elmarco/libvirt,andreabolognani/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,crobinso/libvirt,cbosdo/libvirt,jfehlig/libvirt,taget/libvirt,eskultety/libvirt,agx/libvirt,nertpinx/libvirt,shugaoye/libvirt,nertpinx/libvirt,eskultety/libvirt,libvirt/libvirt,VenkatDatta/libvirt,olafhering/libvirt,taget/libvirt,rlaager/libvirt,andreabolognani/libvirt,nertpinx/libvirt,VenkatDatta/libvirt,zhlcindy/libvirt-1.1.4-maintain,eskultety/libvirt,jfehlig/libvirt,VenkatDatta/libvirt,zhlcindy/libvirt-1.1.4-maintain,eskultety/libvirt,jardasgit/libvirt,rlaager/libvirt,cbosdo/libvirt,jardasgit/libvirt,andreabolognani/libvirt,zippy2/libvirt,cbosdo/libvirt,shugaoye/libvirt,rlaager/libvirt,crobinso/libvirt,jardasgit/libvirt,olafhering/libvirt,elmarco/libvirt,libvirt/libvirt,rlaager/libvirt,jfehlig/libvirt,jfehlig/libvirt,VenkatDatta/libvirt,zippy2/libvirt