Fix(pynn-brainscales): Enforce correct log4cxx version

The production env seems to use a newer spack repo state → log4cxx is newer than currently supported for BrainScaleS → quickfix: pin to old version.

(cherry picked from commit fa396948)

packages/log4cxx/log4cxx-0.10.0-llvm-libcxx.patch

+--- apache-log4cxx-0.10.0/src/main/cpp/stringhelper.cpp2018-04-19 09:48:50.762552	436 +0200
++++ apache-log4cxx-0.10.0-old/src/main/cpp/stringhelper.cpp2	008-04-01 00:34:09.000000000 +0200
+@@ -28,7 +28,6 @@
+ #endif
+ #include <log4cxx/private/log4cxx_private.h>
+ #include <cctype>
+-#include <cstdlib>
+ #include <apr.h>
+ 
+ 
+diff -rpu apache-log4cxx-0.10.0/src/main/include/log4cxx/helpers/simpledateformat.h apache-log4cxx-0.10.0-old/src/main/include/log4cxx/helpers/simpledateformat.h
+--- apache-log4cxx-0.10.0/src/main/include/log4cxx/helpers/simpledateformat.h2018-04-19 09:4	8:19.010260662 +0200
++++ apache-log4cxx-0.10.0-old/src/main/include/log4cxx/helpers/simpledateformat.h2008-04-01 00:34:26.000000000 +0200
+@@ -26,1	0 +26,11 @@
+ 
+ 
+ #include <log4cxx/helpers/dateformat.h>
+-#include <locale>
+ #include <vector>
+ #include <time.h>
+ 
++namespace std { class locale; }
++
+ namespace log4cxx
+ {
+         namespace helpers