procd: fix compiler warning

procd: fix compiler warning

[ 37%] Building C object CMakeFiles/procd.dir/state.c.o
/projects/procd/state.c: In function ‘state_enter’:
/projects/procd/state.c:147:4: error: ignoring return value of ‘chown’, declared with attribute warn_unused_result [-Werror=unused-result]
  147 |    chown(p->pw_dir, p->pw_uid, p->pw_gid);
      |    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
make[2]: *** [CMakeFiles/procd.dir/build.make:89: CMakeFiles/procd.dir/state.c.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:241: CMakeFiles/procd.dir/all] Error 2
make: *** [Makefile:130: all] Error 2

Signed-off-by: John Crispin <john@phrozen.org>