Add "ppc64le" as a valid RPM package architecture

[meaksh]

What does this PR do?

This PR fixes an issue when dealing with RPM packages that have "ppc64le" architecture.

Currently, the Salt jobs for installing (or updating) packages with this architecture are set as failed even if the packages get installed.

Previous Behavior

salt/job/20190524170336946386/ret/sles12sp4-ppc64le.tf.local      {
    "_stamp": "2019-05-24T15:06:22.838525",
    "cmd": "_return",
    "fun": "state.apply",
    "fun_args":

...

    "out": "highstate",
    "retcode": 2,
    "return": {
        "pkg_|-pkg_installed_|-pkg_installed_|-installed": {
            "__id__": "pkg_installed",
            "__run_num__": 1,
            "__sls__": "packages.pkginstall",
            "changes": {
                "logrotate": {
                    "new": [
                        {
                            "arch": "ppc64le",
                            "epoch": null,
                            "install_date_time_t": 1558710317,
                            "release": "2.14.1",
                            "version": "3.11.0"
                        }
                    "old": [
                        {
                            "arch": "ppc64le",
                            "epoch": null,
                            "install_date_time_t": 1558700624,
                            "release": "2.11.1",
                            "version": "3.11.0"
                        }
                    ]
                }
            },
            "comment": "The following packages failed to install/update: logrotate.ppc64le=3.11.0-2.14.1",
            "duration": 130682.749,
            "name": "pkg_installed",
            "result": false,
            "start_time": "16:04:11.071441"
        }
    },
    "success": true
}

New Behavior

salt/job/20190524170336946386/ret/sles12sp4-ppc64le.tf.local      {
    "_stamp": "2019-05-24T15:06:22.838525",
    "cmd": "_return",
    "fun": "state.apply",
    "fun_args":

...

       "pkg_|-pkg_installed_|-pkg_installed_|-installed": {
            "__id__": "pkg_installed",
            "__run_num__": 1,
            "__sls__": "packages.pkginstall",
            "changes": {
                "logrotate": {
                    "new": [
                        {
                            "arch": "ppc64le",
                            "epoch": null,
                            "install_date_time_t": 1558712943,
                            "release": "2.14.1",
                            "version": "3.11.0"
                        }
                    ],
                    "old": [
                        {
                            "arch": "ppc64le",
                            "epoch": null,
                            "install_date_time_t": 1558712632,
                            "release": "2.11.1",
                            "version": "3.11.0"
                        }
                    ]
                }
            },
            "comment": "1 targeted package was installed/updated.",
            "duration": 150933.562,
            "name": "pkg_installed",
            "result": true,
            "start_time": "16:47:50.598440"
        }
    },
    "success": true
}

Tests written?

No

Commits signed with GPG?

Yes