adding testbuild to rhel5 makefile

[Joel Andres Granados <jgranado redhat com>]

Hi list:

Here is a patch to current Makefile that tries to avoid the build errors that I had last week.  It basically adds a "testbuild" target so its easier for the person building anaconda to test the build.  The testbuild target will not create a tag because its just a test build:)
Commets greatly appreciated.