Revert "core: increase SHM memory pool to 128 MB"

- This reverts commit 063e6a025b8ca0163af2147f057d29447c6f9760.
- to be added as comment to default sysconfig packaging files

src/core/config.h

@@ -142,7 +142,7 @@
 #endif
 #define PKG_MEM_POOL_SIZE PKG_MEM_SIZE*1024*1024	/*!< used only if PKG_MALLOC is defined*/
 
-#define SHM_MEM_SIZE 128				/*!< used if SH_MEM is defined*/
+#define SHM_MEM_SIZE 64				/*!< used if SH_MEM is defined*/
 #define SHM_MEM_POOL_SIZE SHM_MEM_SIZE*1024*1024
 
 /* dimensioning buckets in q_malloc */