[PATCH v2] Remove NLS check for KWallet support and reorder private includes

Following Daniel's suggestions in previous thread, attached is another
iteration of the patch that removes the need for NLS to be enabled for
KWallet support to be built.

Besides removing the NLS check from kwallet.m4 as the previous patch
did, this one also reorders the includes in kwallet.cpp so that the
private Subversion includes come after the system/KDE ones. The same has
been done to the GNOME Keyring code, as well as another file.

In most of the cases, svn_private_config.h is already one of the last
files to be included, and I felt it was too dangerous to change the
cases where it was included before some feature checks or apr includes.