Description of problem:
Satellite 5.6.0 installer on s390x claims that some packages are not installed although these packages are installed.

Version-Release number of selected component (if applicable):
Satellite 5.6.0 (Satellite-5.6.0-RHEL6-re20130927.0) @ s390x @ EmbPostgreSQL

How reproducible:
always

Steps to Reproduce:
1. install Satellite 5.6.0 @ s390x
2. check the output + /var/log/rhn/rhn_installation.log
3. check "not-installed" packages by `rpm -q ...`

Actual results:
[...]
* Checking for uninstalled prerequisites.
There are some packages from Red Hat Enterprise Linux that are not part
of the @base group that Satellite will require to be installed on this
system. The installer will try resolve the dependencies automatically.
* Installing RHN packages.
Warning: yum did not install the following packages:
        antlr
        jakarta-commons-codec
        jakarta-commons-el
        jakarta-commons-lang
        jakarta-oro
        jdom
        mtools
        objectweb-asm
        perl-Class-MethodMaker
        perl-Class-Singleton
        perl-DateTime
        perl-List-MoreUtils
        perl-Params-Validate
        perl-TermReadKey
        syslinux
        xalan-j2
* Now running spacewalk-setup.
[...]

$ rpm -q ...
antlr-2.7.7-7.ep5.el6.noarch
jakarta-commons-codec-1.3-11.7.el6.s390x
jakarta-commons-el-1.0-19.2.1.1.ep5.el6.noarch
jakarta-commons-lang-2.4-1.1.el6.noarch
jakarta-oro-2.0.8-6.6.el6.s390x
jdom-1.1.1-1.el6.noarch
package mtools is not installed
objectweb-asm-3.2-2.1.el6.noarch
perl-Class-MethodMaker-2.16-4.el6.s390x
perl-Class-Singleton-1.4-6.el6.noarch
perl-DateTime-0.5300-1.el6.s390x
perl-List-MoreUtils-0.22-10.el6.s390x
perl-Params-Validate-0.92-3.el6.s390x
perl-TermReadKey-2.30-13.el6.s390x
package syslinux is not installed
xalan-j2-2.7.0-9.8.el6.noarch

Expected results:
All needed packages are installed and the installer knows about it.

Additional info:
only mtools and syslinux weren't installed