init: make LIBISCSI_CACHE_ALLOCATIONS a public environment variable

this variable was introduced for iscsi-test-cu only. This patch
makes it a generic environment variable that can be set per context.

Signed-off-by: Peter Lieven <pl@kamp.de>

test-tool/iscsi-test-cu.c

@@ -971,11 +971,6 @@ main(int argc, char *argv[])
 	};
 	int i, c;
 	int opt_idx = 0;
-	char *ca;
-
-	ca = getenv("LIBISCSI_CACHE_ALLOCATIONS");
-	if (ca && atoi(ca) == 0)
-		iscsi_set_cache_allocations(0);
 
 	sd = malloc(sizeof(struct scsi_device));
 	memset(sd, '\0', sizeof(struct scsi_device));