Update u_e-dovecot-mail-crypt.md

docs/u_e-dovecot-mail-crypt.md

@@ -10,9 +10,13 @@ find /var/vmail/ -type f -regextype egrep -regex '.*S=.*W=.*' | while read -r fi
 if [[ $(head -c7 "$file") == "CRYPTED" ]]; then
 doveadm fs get crypt private_key_path=/mail_crypt/ecprivkey.pem:public_key_path=/mail_crypt/ecpubkey.pem:posix:prefix=/ \
   "$file" > "/tmp/$(basename "$file")"
+  if [[ -s "/tmp/$(basename "$file")" ]]; then
     chmod 600 "/tmp/$(basename "$file")"
     chown 5000:5000 "/tmp/$(basename "$file")"
     mv "/tmp/$(basename "$file")" "$file"
+  else
+    rm "/tmp/$(basename "$file")"
+  fi
 fi
 done