Fix potential vulnerable cloned function

[npt-1707]

Hi Development Team,

I identified a potential vulnerability in a clone function sdsMakeRoomFor()
in src/shell/sds/sds.c sourced from redis/redis.
This issue, originally reported in CVE-2021-41099,
was resolved in the repository via this commit redis/redis@c6ad876.

This PR applies the corresponding patch to fix the vulnerability in this codebase.

Please review at your convenience. Thank you!

[acelyc111]

@npt-1707 Thanks for the contribution!

[empiredan]

Compilation failed with the following error:

[ 95%] Building C object src/shell/CMakeFiles/pegasus_shell.dir/sds/sds.c.o
/__w/incubator-pegasus/incubator-pegasus/src/shell/sds/sds.c: In function 'sdsMakeRoomFor':
/__w/incubator-pegasus/incubator-pegasus/src/shell/sds/sds.c:200:25: error: variable 'reqlen' set but not used [-Werror=unused-but-set-variable]
  200 |     size_t len, newlen, reqlen;
      |                         ^~~~~~
/__w/incubator-pegasus/incubator-pegasus/src/shell/sds/sds.c: At top level:
cc1: note: unrecognized command-line option '-Wno-inconsistent-missing-override' may have been intended to silence earlier diagnostics
cc1: all warnings being treated as errors
make[2]: *** [src/shell/CMakeFiles/pegasus_shell.dir/build.make:303: src/shell/CMakeFiles/pegasus_shell.dir/sds/sds.c.o] Error 1
make[2]: *** Waiting for unfinished jobs....
[ 95%] Building CXX object src/server/test/CMakeFiles/pegasus_unit_test.dir/__/pegasus_server_impl.cpp.o
[ 95%] Building CXX object src/server/CMakeFiles/pegasus_server.dir/rocksdb_wrapper.cpp.o
make[1]: *** [CMakeFiles/Makefile2:3916: src/shell/CMakeFiles/pegasus_shell.dir/all] Error 2
make[1]: *** Waiting for unfinished jobs....

The root cause is that the CI builds in release mode (see lint_and_test_cpp.yaml#L119), rather than in debug mode. In release mode, the statement assert(hdrlen + newlen + 1 > reqlen); gets optimized away, leading to the compiler warning that reqlen is set but not used.

In fact, the same purpose can be achieved without using the reqlen variable by assert(hdrlen + newlen + 1 > len + addlen);. However, doing so would introduce a significant difference from the changes in redis/redis@c6ad876, which may lead to more conflicts when merging code in the future. Therefore, we can use (void) to silence the unused variable warning for reqlen to solve this problem at the lowest cost.