Move character escaping function to ipautil

Functions `escape_seq` and `unescape_seq` have a generic use-case so it makes
sense to move them from `kerberos` to ipautil module so that other modules can
reuse them more readily.

https://fedorahosted.org/freeipa/ticket/5809

Reviewed-By: Tomas Krizek <tkrizek@redhat.com>

ipapython/ipautil.py

@@ -1487,3 +1487,30 @@ def is_fips_enabled():
         # Consider that the host is not fips-enabled if the file does not exist
         pass
     return False
+
+
+def unescape_seq(seq, *args):
+    """
+    unescape (remove '\\') all occurences of sequence in input strings.
+
+    :param seq: sequence to unescape
+    :param args: input string to process
+
+    :returns: tuple of strings with unescaped sequences
+    """
+    unescape_re = re.compile(r'\\{}'.format(seq))
+
+    return tuple(re.sub(unescape_re, seq, a) for a in args)
+
+
+def escape_seq(seq, *args):
+    """
+    escape (prepend '\\') all occurences of sequence in input strings
+
+    :param seq: sequence to escape
+    :param args: input string to process
+
+    :returns: tuple of strings with escaped sequences
+    """
+
+    return tuple(a.replace(seq, u'\\{}'.format(seq)) for a in args)

ipapython/kerberos.py

@@ -8,6 +8,8 @@ classes/utils for Kerberos principal name validation/manipulation
 import re
 import six
 
+from ipapython.ipautil import escape_seq, unescape_seq
+
 if six.PY3:
     unicode = str
 
@@ -58,33 +60,6 @@ def split_principal_name(principal_name):
     return tuple(COMPONENT_SPLIT_RE.split(principal_name))
 
 
-def unescape_seq(seq, *args):
-    """
-    unescape (remove '\\') all occurences of sequence in input strings.
-
-    :param seq: sequence to unescape
-    :param args: input string to process
-
-    :returns: tuple of strings with unescaped sequences
-    """
-    unescape_re = re.compile(r'\\{}'.format(seq))
-
-    return tuple(re.sub(unescape_re, seq, a) for a in args)
-
-
-def escape_seq(seq, *args):
-    """
-    escape (prepend '\\') all occurences of sequence in input strings
-
-    :param seq: sequence to escape
-    :param args: input string to process
-
-    :returns: tuple of strings with escaped sequences
-    """
-
-    return tuple(a.replace(seq, u'\\{}'.format(seq)) for a in args)
-
-
 @six.python_2_unicode_compatible
 class Principal(object):
     """