Please describe the problem:

If the msgid_plural string in po file contains empty string, the gtranslator
merge msgid and it's corresponding msgid_plural as one string.

Steps to reproduce:
1. creat a simple po file:

msgid ""
msgstr ""
"Project-Id-Version: update-manager HEAD\n"
"Report-Msgid-Bugs-To: \n"
"POT-Creation-Date: 2005-05-12 12:08+0000\n"
"PO-Revision-Date: 2005-06-09 21:04+0800\n"
"Last-Translator: Ye Zhuqiu <yezhuqiu@gmail.com>\n"
"Language-Team: zh_CN <i18n-translation@lists.linux.net.cn>\n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=UTF-8\n"
"Content-Transfer-Encoding: 8bit\n"
"Plural-Forms: nplurals=1; plural=0;"

msgid ""
"%s package"
msgid_plural ""
"%s packages"
msgstr[0] ""
msgstr[1] ""

2. open the po file in gtranslator

Actual results:
in the original text window, msgid and msgid_plural merge into one string, such as:

%s package
%s packages

Expected results:

gtranslator should recognise msgid and msgid_plural properly.

Does this happen every time?
yes

Other information:
if msgid_plural contain no empty string, such as:

msgid ""
"%s package"
msgid_plural "%s packages"
msgstr[0] ""
msgstr[1] ""

gtranslator will work properly.