installer: Change installer privileges to 'lowest'

Allows the installer to be run with normal user permissions again.

While http://www.innosetup.org/ishelp/topic_setup_privilegesrequired.htm
does not list `none` as a valid value http://jrsoftware.github.io/issrc/whatsnew.htm
says:

  If you were using PrivilegesRequired=none before, it is recommended to switch
  to PrivilegesRequired=lowest.

which is what this fix does.  The previous value of `admin` was too high.

Tested locally with the 64 bit build.

Fixes git-for-windows/git#497

Signed-off-by: Jeremy Kolb <[email protected]>

Author: kjeremy

installer/install.iss

@@ -55,11 +55,7 @@ DefaultGroupName={#APP_NAME}
 DisableProgramGroupPage=auto
 DisableReadyPage=yes
 InfoBeforeFile={#SourcePath}\gpl-2.0.rtf
-#ifdef OUTPUT_TO_TEMP
 PrivilegesRequired=lowest
-#else
-PrivilegesRequired=poweruser
-#endif
 UninstallDisplayIcon={app}\{#MINGW_BITNESS}\share\git\git-for-windows.ico
 #ifndef COMPILE_FROM_IDE
 #if Pos('-',APP_VERSION)>0