compiler warnings

test-tool/0182_writesame10_beyondeol.c

@@ -28,7 +28,7 @@ int T0182_writesame10_beyondeol(const char *initiator, const char *url, int data
 	int ret, i, lun;
 	uint32_t block_size;
 	uint64_t num_blocks;
-	char buf[512];
+	unsigned char buf[512];
 
 	printf("0182_writesame10_beyondeol:\n");
 	printf("=======================\n");

test-tool/0183_writesame10_wrprotect.c

@@ -28,7 +28,7 @@ int T0183_writesame10_wrprotect(const char *initiator, const char *url, int data
 	int ret, i, lun;
 	uint32_t block_size;
 	uint64_t num_blocks;
-	char buf[512];
+	unsigned char buf[512];
 
 	printf("0183_writesame10_wrptotect:\n");
 	printf("=======================\n");

test-tool/0184_writesame10_0blocks.c

@@ -25,7 +25,7 @@ int T0184_writesame10_0blocks(const char *initiator, const char *url, int data_l
 	struct iscsi_context *iscsi;
 	struct scsi_task *task;
 	struct scsi_readcapacity16 *rc16;
-	int ret, i, lun;
+	int ret, lun;
 	uint32_t block_size;
 	uint64_t num_blocks;
 	unsigned char buf[512];

test-tool/0193_writesame16_wrprotect.c

@@ -28,7 +28,7 @@ int T0193_writesame16_wrprotect(const char *initiator, const char *url, int data
 	int ret, i, lun;
 	uint32_t block_size;
 	uint64_t num_blocks;
-	char buf[512];
+	unsigned char buf[512];
 
 	printf("0193_writesame16_wrptotect:\n");
 	printf("=======================\n");

test-tool/0194_writesame16_0blocks.c

@@ -25,7 +25,7 @@ int T0194_writesame16_0blocks(const char *initiator, const char *url, int data_l
 	struct iscsi_context *iscsi;
 	struct scsi_task *task;
 	struct scsi_readcapacity16 *rc16;
-	int ret, i, lun;
+	int ret, lun;
 	uint32_t block_size;
 	uint64_t num_blocks;
 	unsigned char buf[512];