[wp] fix cmd & cache issues

bin/wp-qualif.sh

 export FRAMAC_WP_CACHE=update
-export FRAMAC_WP_CACHEDIR=$(WP_QUALIF_CACHE)
+export FRAMAC_WP_CACHEDIR=$WP_QUALIF_CACHE

src/plugins/wp/tests/wp_plugin/oracle_qualif/removed.res.oracle

@@ -5,7 +5,7 @@
 [eva] Initial state computed
 [eva:initial-state] Values of globals at initialization
   
-[eva:alarm] tests/wp_plugin/removed.i:10: Warning: 
+[eva:alarm] tests/wp_plugin/removed.i:9: Warning: 
   signed overflow. assert 1 + i ≤ 2147483647;
 [eva] done for function main
 [eva] ====== VALUES COMPUTED ======
@@ -18,5 +18,10 @@
 [wp] [Alt-Ergo] Goal typed_main_assert_Eva_signed_overflow : Unsuccess
 [wp] Proved goals:    0 / 1
   Alt-Ergo:        0  (unsuccess: 1)
+------------------------------------------------------------
+ Functions                 WP     Alt-Ergo  Total   Success
+  main                      -        -        1       0.0%
+------------------------------------------------------------
 [wp] Running WP plugin...
 [wp] Warning: No goal generated
+------------------------------------------------------------

src/plugins/wp/tests/wp_plugin/removed.i

 /* run.config_qualif
-   CMD: @frama-c@ -wp-share ./share -wp-msg-key shell -wp-par 1 -wp-session @PTEST_DIR@/oracle@PTEST_CONFIG@/@PTEST_NAME@.@PTEST_NUMBER@.session -wp-cache replay -wp-cache-env
-   OPT: -eva -eva-msg-key=-summary -then -wp -then -no-eva -warn-unsigned-overflow -wp
+   OPT: -load-module eva,scope -no-wp -eva -eva-msg-key=-summary -then -wp -then -no-eva -warn-unsigned-overflow -wp
  */
 
 /* run.config