Check whether yum file or URL install is an upgrade (#4547)

Rather than just checking whether a package with the right
name is installed, use `local_nvra` to check whether the
version/release/arch differs too.

Remove `local_name` as it is a shortcut too far.

Fixes #3807
Fixes #4529

lib/ansible/modules/packaging/os/yum.py

@@ -512,19 +512,6 @@ def local_nvra(module, path):
                             header[rpm.RPMTAG_RELEASE],
                             header[rpm.RPMTAG_ARCH])
 
-def local_name(module, path):
-    """return package name of a local rpm passed in"""
-
-    ts = rpm.TransactionSet()
-    ts.setVSFlags(rpm._RPMVSF_NOSIGNATURES)
-    fd = os.open(path, os.O_RDONLY)
-    try:
-        header = ts.hdrFromFdno(fd)
-    finally:
-        os.close(fd)
-
-    return header[rpm.RPMTAG_NAME]
-    
 def pkg_to_dict(pkgstr):
 
     if pkgstr.strip():
@@ -599,10 +586,10 @@ def install(module, items, repoq, yum_basecmd, conf_file, en_repos, dis_repos):
                 res['msg'] += "No Package file matching '%s' found on system" % spec
                 module.fail_json(**res)
 
-            pkg_name = local_name(module, spec)
+            nvra = local_nvra(module, spec)
 
             # look for them in the rpmdb
-            if is_installed(module, repoq, pkg_name, conf_file, en_repos=en_repos, dis_repos=dis_repos):
+            if is_installed(module, repoq, nvra, conf_file, en_repos=en_repos, dis_repos=dis_repos):
                 # if they are there, skip it
                 continue
             pkg = spec
@@ -611,8 +598,8 @@ def install(module, items, repoq, yum_basecmd, conf_file, en_repos, dis_repos):
         elif '://' in spec:
             # download package so that we can check if it's already installed
             package = fetch_rpm_from_url(spec, module=module)
-            pkg_name = local_name(module, package)
-            if is_installed(module, repoq, pkg_name, conf_file, en_repos=en_repos, dis_repos=dis_repos):
+            nvra = local_nvra(module, package)
+            if is_installed(module, repoq, nvra, conf_file, en_repos=en_repos, dis_repos=dis_repos):
                 # if it's there, skip it
                 continue
             pkg = package