Change the URL of where the installation instructions are, they've moved to...

Change the URL of where the installation instructions are, they've moved to the new wiki. Part of a fix for #1738

README

@@ -4,7 +4,7 @@ Mahara Readme
 Thanks for downloading Mahara! Currently, things are very much in a development
 phase. To install, please follow the instructions here:
 
-  https://eduforge.org/wiki/wiki/mahara/wiki?pagename=MaharaInstallInstructions
+  http://www.mahara.org/wiki/En/Sysadmin_Guide/Installing_Mahara
 
 Lots of chat is happening right now in #mahara on freenode. If you have
 questions, suggestions or ideas, please join us!