py3: write CA/KRA config into file opened in text mode

config parser writes data as text so CA/KRA should be opened in textual
mode otherwise type errors are raised from installer

https://fedorahosted.org/freeipa/ticket/4985

Reviewed-By: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Jan Cholasta <jcholast@redhat.com>

ipaserver/install/cainstance.py

@@ -599,7 +599,7 @@ class CAInstance(DogtagInstance):
         config.set("Tomcat", "pki_ajp_host", "::1")
 
         # Generate configuration file
-        with open(cfg_file, "wb") as f:
+        with open(cfg_file, "w") as f:
             config.write(f)
 
         self.backup_state('installed', True)

ipaserver/install/krainstance.py

@@ -263,7 +263,7 @@ class KRAInstance(DogtagInstance):
                 admin_path.write(cert)
 
         # Generate configuration file
-        with open(cfg_file, "wb") as f:
+        with open(cfg_file, "w") as f:
             config.write(f)
 
         try: