diff -up yum-3.4.3/yum/igroups.py.old yum-3.4.3/yum/igroups.py

--- yum-3.4.3/yum/igroups.py.old	2015-09-09 16:18:23.494390878 +0200

+++ yum-3.4.3/yum/igroups.py	2015-09-09 17:10:33.451517354 +0200

@@ -43,6 +43,12 @@ def _makedirs_no_umask(*args):

     return ret

+def _read_str(fo):

+    for s in fo:

+        if s[:-1]:

+            return s[:-1]

+    return ''

+

 class InstalledGroup(object):

     def __init__(self, gid):

         self.gid       = gid

@@ -107,11 +113,11 @@ class InstalledGroups(object):

         if not os.access(self.filename, os.R_OK):

             return

-        def _read_str(fo):

-            return fo.readline()[:-1]

-

         fo = open(self.filename)

-        ver = int(_read_str(fo))

+        try:

+            ver = int(_read_str(fo))

+        except ValueError:

+            return

         if ver != 1:

             return

@@ -132,11 +138,11 @@ class InstalledGroups(object):

         if not os.access(self.grp_filename, os.R_OK):

             return

-        def _read_str(fo):

-            return fo.readline()[:-1]

-

         fo = open(self.grp_filename)

-        ver = int(_read_str(fo))

+        try:

+            ver = int(_read_str(fo))

+        except ValueError:

+            return

         if ver != 1:

             return