Remove unused variables

[motiwari]

Hi, thanks for making this code. We are using it in https://github.com/ThrunGroup/BanditPAM.

When compiling the code we get the following warnings:

headers/carma/include/carma_bits/cnumpy.h:277:9: warning: unused variable 'ret_code' [-Wunused-variable]
      int ret_code = api.PyArray_CopyInto_(tmp, src);
          ^
  In file included from src/banditpam.cpp:8:
  In file included from headers/kmedoids_algorithm.hpp:4:
  In file included from headers/log_helper.hpp:4:
  In file included from headers/carma/include/carma:59:
  In file included from headers/carma/include/carma_bits/arraystore.h:25:
  In file included from headers/carma/include/carma_bits/converters.h:29:
  headers/carma/include/carma_bits/numpytoarma.h:93:13: warning: unused variable 'dims' [-Wunused-variable]
      ssize_t dims = src.ndim;
              ^
  headers/carma/include/carma_bits/numpytoarma.h:168:13: warning: unused variable 'dims' [-Wunused-variable]
      ssize_t dims = src.ndim;
              ^
  headers/carma/include/carma_bits/numpytoarma.h:224:13: warning: unused variable 'dims' [-Wunused-variable]
      ssize_t dims = src.ndim;
              ^
  headers/carma/include/carma_bits/numpytoarma.h:281:13: warning: unused variable 'dims' [-Wunused-variable]
      ssize_t dims = src.ndim;
              ^
  5 warnings generated.

[RUrlus]

@motiwari Thanks for reporting, Clangd doesn't seem to want to catch these for some reason.
Fixed in 2cced75.

I'll create a new release later today which will include this