Fix grammar of messages printed via pam_prompt

Fix grammar of messages printed via pam_prompt

Turn into proper sentences those messages that are printed without
further modifications using pam_prompt in contexts where proper
sentences are expected.

* libpam/pam_get_authtok.c (pam_get_authtok_internal): Fix grammar
of the message passed to pam_error.
* modules/pam_limits/pam_limits.c (pam_sm_open_session): Likewise.
* modules/pam_cracklib/pam_cracklib.c (_pam_unix_approve_pass): Fix
grammar of error messages passed to pam_error.
* modules/pam_mail/pam_mail.c (report_mail): Fix grammar of a message
passed to pam_info.
* modules/pam_timestamp/pam_timestamp.c (verbose_success): Likewise.
* modules/pam_selinux/pam_selinux.c (config_context, send_text): Fix
grammar of messages passed to pam_prompt.
* modules/pam_tally/pam_tally.c (tally_check): Fix grammar of messages
passed to pam_info.
* modules/pam_tally2/pam_tally2.c (tally_check): Likewise.
* modules/pam_unix/pam_unix_acct.c (pam_sm_acct_mgmt): Fix grammar
of messages passed to _make_remark.
* modules/pam_unix/pam_unix_passwd.c (_pam_unix_approve_pass,
pam_sm_chauthtok): Likewise.
* po/Linux-PAM.pot: Regenerate.