A system upgraded from RHEL6 to RHEL7 fails to update

Issue

• After upgrading a RHEL6 server to RHEL7, next yum update fails due to missing requirements.

    ERROR with transaction check vs depsolve:
    python(abi) = 2.6 is needed by (installed) python-crypto-2.0.1-22.el6.x86_64
    python(abi) = 2.6 is needed by (installed) libproxy-python-0.3.0-10.el6.x86_64
    python(abi) = 2.6 is needed by (installed) python-iwlib-0.1-1.2.el6.x86_64
    python(abi) = 2.6 is needed by (installed) cas-0.15-1.el6.1.noarch
    ** Found 26 pre-existing rpmdb problem(s), 'yum check' output follows:
    apr-util-ldap-1.3.9-3.el6_0.1.x86_64 has missing requires of apr-util = ('0', '1.3.9', '3.el6_0.1')
    cas-0.15-1.el6.1.noarch has missing requires of python(abi) = ('0', '2.6', None)
    hal-info-20090716-5.el6.noarch has missing requires of hal >= ('0', '0.5.10', None)
    libproxy-bin-0.3.0-10.el6.x86_64 has missing requires of libproxy = ('0', '0.3.0', '10.el6')
    libproxy-bin-0.3.0-10.el6.x86_64 has missing requires of libproxy.so.0()(64bit)
    libproxy-python-0.3.0-10.el6.x86_64 has missing requires of libproxy = ('0', '0.3.0', '10.el6')
    libproxy-python-0.3.0-10.el6.x86_64 has missing requires of python(abi) = ('0', '2.6', None)
    libreport-compat-2.0.9-34.el6.x86_64 has missing requires of libreport = ('0', '2.0.9', '34.el6')
    libreport-compat-2.0.9-34.el6.x86_64 has missing requires of libreport-plugin-rhtsupport = ('0', '2.0.9', '34.el6')
    libreport-plugin-kerneloops-2.0.9-34.el6.x86_64 has missing requires of libabrt_web.so.0()(64bit)
    libreport-plugin-kerneloops-2.0.9-34.el6.x86_64 has missing requires of libproxy.so.0()(64bit)
    libreport-plugin-kerneloops-2.0.9-34.el6.x86_64 has missing requires of libreport = ('0', '2.0.9', '34.el6')
    libreport-plugin-logger-2.0.9-34.el6.x86_64 has missing requires of libreport = ('0', '2.0.9', '34.el6')
    openscap-engine-sce-1.2.13-2.el6.x86_64 has missing requires of libpcre.so.0()(64bit)
    openscap-engine-sce-1.2.13-2.el6.x86_64 has missing requires of librpm.so.1()(64bit)
    openscap-engine-sce-1.2.13-2.el6.x86_64 has missing requires of librpmio.so.1()(64bit)
    openscap-engine-sce-1.2.13-2.el6.x86_64 has missing requires of openscap = ('0', '1.2.13', '2.el6')
    python-crypto-2.0.1-22.el6.x86_64 has missing requires of libgmp.so.3()(64bit)
    python-crypto-2.0.1-22.el6.x86_64 has missing requires of libpython2.6.so.1.0()(64bit)
    python-crypto-2.0.1-22.el6.x86_64 has missing requires of python(abi) = ('0', '2.6', None)
    python-iwlib-0.1-1.2.el6.x86_64 has missing requires of libpython2.6.so.1.0()(64bit)
    python-iwlib-0.1-1.2.el6.x86_64 has missing requires of python(abi) = ('0', '2.6', None)
    1:readahead-1.5.6-2.el6.x86_64 has missing requires of upstart
    system-config-firewall-tui-1.2.27-7.2.el6_6.noarch has missing requires of system-config-firewall-base = ('0', '1.2.27', '7.2.el6_6')
    xz-lzma-compat-4.999.9-0.5.beta.20091007git.el6.x86_64 has missing requires of liblzma.so.0()(64bit)
    xz-lzma-compat-4.999.9-0.5.beta.20091007git.el6.x86_64 has missing requires of xz = ('0', '4.999.9', '0.5.beta.20091007git.el6')