librados: remove new setxattr overload to avoid breaking the C++ ABI

[jdurgin]

http://tracker.ceph.com/issues/18059

[yuriw]

test this please

[theanalyst]

@jdurgin @liewegas this is the result of the rgw run on this http://pulpito.ceph.com/abhi-2016-12-01_22:19:07-rgw-wip-jewel-10-2-4-rc-distro-basic-smithi/ , basically we've had 3 jobs fail due to valgrind failures on ceph-mon, (which was seen across other runs as well) otherwise looks green

[jdurgin]

this looks good to go then, thanks!

FTR, the leak listed there looks like it's coming from valgrind itself:

  <unique>0x52</unique>
  <tid>1</tid>
  <kind>Leak_StillReachable</kind>
  <xwhat>
    <text>72,704 bytes in 1 blocks are still reachable in loss record 83 of 84</text>
    <leakedbytes>72704</leakedbytes>
    <leakedblocks>1</leakedblocks>
  </xwhat>
  <stack>
    <frame>
      <ip>0xA885B8F</ip>
      <obj>/usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so</obj>
      <fn>malloc</fn>
    </frame>
    <frame>
      <ip>0xC79FEFF</ip>
      <obj>/usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21</obj>
    </frame>
    <frame>
      <ip>0x9C684E9</ip>
      <obj>/lib/x86_64-linux-gnu/ld-2.23.so</obj>
      <fn>call_init.part.0</fn>
      <dir>/build/glibc-Qz8a69/glibc-2.23/elf</dir>
      <file>dl-init.c</file>
      <line>72</line>
    </frame>
    <frame>
      <ip>0x9C685FA</ip>
      <obj>/lib/x86_64-linux-gnu/ld-2.23.so</obj>
      <fn>call_init</fn>
      <dir>/build/glibc-Qz8a69/glibc-2.23/elf</dir>
      <file>dl-init.c</file>
      <line>30</line>
    </frame>
    <frame>
      <ip>0x9C685FA</ip>
      <obj>/lib/x86_64-linux-gnu/ld-2.23.so</obj>
      <fn>_dl_init</fn>
      <dir>/build/glibc-Qz8a69/glibc-2.23/elf</dir>
      <file>dl-init.c</file>
      <line>120</line>
    </frame>
    <frame>
      <ip>0x9C58CF9</ip>
      <obj>/lib/x86_64-linux-gnu/ld-2.23.so</obj>
    </frame>
    <frame>
      <ip>0x5</ip>
    </frame>
    <frame>
      <ip>0xFFF000C1E</ip>
    </frame>
    <frame>
      <ip>0xFFF000C27</ip>
    </frame>
    <frame>
      <ip>0xFFF000C2A</ip>
    </frame>
    <frame>
      <ip>0xFFF000C34</ip>
    </frame>
    <frame>
      <ip>0xFFF000C39</ip>
    </frame>
    <frame>
      <ip>0xFFF000C3C</ip>
    </frame>
  </stack>
</error>