Munin API submodules modify paths upon enable/disable, not install.

modules/munin_apc/munin_apc.install

@@ -11,8 +11,15 @@
  */
 
 /**
- * Implements hook_install().
+ * Implements hook_enable().
  */
-function munin_apc_install() {
+function munin_apc_enable() {
+  variable_set('menu_rebuild_needed', TRUE);
+}
+
+/**
+ * Implements hook_disable().
+ */
+function munin_apc_disable() {
   variable_set('menu_rebuild_needed', TRUE);
 }

modules/munin_core/munin_core.install

@@ -11,8 +11,15 @@
  */
 
 /**
- * Implements hook_install().
+ * Implements hook_enable().
  */
-function munin_core_install() {
+function munin_core_enable() {
+  variable_set('menu_rebuild_needed', TRUE);
+}
+
+/**
+ * Implements hook_disable().
+ */
+function munin_core_disable() {
   variable_set('menu_rebuild_needed', TRUE);
 }