[2/2]Fixes char to unsigned char for byte representation

        The forcing of signed char type was introduced by 3fb3bb5d38r,
"configure: force 'char' type to be signed (#4025)".

        Thus at xlators/features/compress/src/cdc-helper.c was found the
use of a char type to represent bytes, when it should be using an unsigned
type to avoid sign extension and overflow.

        This commit changes the variable "gzip_header" to "unsigned" type.

Signed-off-by: Thales Antunes de Oliveira Barretto <thales.barretto.git@gmail.com>
#  xlators/features/compress/src/cdc-helper.c | 4 ++--
#  1 file changed, 2 insertions(+), 2 deletions(-)
#  xlators/features/compress/src/cdc-helper.c | 4 ++--
#  1 file changed, 2 insertions(+), 2 deletions(-)
#  xlators/features/compress/src/cdc-helper.c | 4 ++--
#  1 file changed, 2 insertions(+), 2 deletions(-)

Author: ThalesBarretto

xlators/features/compress/src/cdc-helper.c

@@ -30,8 +30,8 @@
  * gzip_header is added only during debugging.
  * Refer to the function cdc_dump_iovec_to_disk
  */
-static const char gzip_header[10] = {'\037', '\213', Z_DEFLATED,  0, 0, 0, 0,
-                                     0,      0,      GF_CDC_OS_ID};
+static const unsigned char gzip_header[10] = {
+    '\037', '\213', Z_DEFLATED, 0, 0, 0, 0, 0, 0, GF_CDC_OS_ID};
 
 static int32_t
 cdc_next_iovec(cdc_info_t *ci)