Move install script error handling to a common function

All of our install/admin scripts had a try/except block calling the
main function and handling common exceptions. These were copy-pasted
from each other and modified to various levels of sophistication.
This refactors them out of installers to a single function, which
includes a final pass/fail message for all of the scripts.

Non-install scripts that set up the same log handler levels for
stderr and log file are not changed, as it's not possible to log
to only the logfile without changing the logger configuration.

https://fedorahosted.org/freeipa/ticket/2071

install/tools/ipa-server-certinstall

@@ -31,6 +31,7 @@ from ipapython.ipautil import user_input
 
 from ipaserver.install import certs, dsinstance, httpinstance, installutils
 from ipalib import api
+from ipapython.ipa_log_manager import *
 from ipaserver.plugins.ldap2 import ldap2
 
 def get_realm_name():
@@ -120,12 +121,17 @@ def import_cert(dirname, pkcs12_fname, pkcs12_passwd, db_password):
     return server_cert
 
 def main():
+    if os.geteuid() != 0:
+        sys.exit("\nYou must be root to run this script.\n")
+
     installutils.check_server_configuration()
 
     options, pkcs12_fname = parse_options()
 
     cfg = dict(in_server=True,)
 
+    standard_logging_setup("/var/log/ipa/default.log")
+
     api.bootstrap(**cfg)
     api.finalize()
 
@@ -165,12 +171,5 @@ def main():
 
     return 0
 
-try:
-    if not os.geteuid()==0:
-        sys.exit("\nYou must be root to run this script.\n")
-
-    main()
-except SystemExit, e:
-    sys.exit(e)
-except RuntimeError, e:
-    sys.exit(e)
+if __name__ == '__main__':
+    installutils.run_script(main, operation_name='ipa-server-certinstall')