graph_blockmodel.hh: Cosmetic changes

6 jobs for master in 312 minutes and 24 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #2271
amd64
job_clang_amd64

05:12:24

passed #2275
amd64
job_clang_amd64_nosh

05:08:28

passed #2273
amd64
job_clang_py2_amd64

05:07:24

passed #2270
amd64
job_gcc_amd64

02:56:45

passed #2274
amd64
job_gcc_amd64_nosh

03:49:57

passed #2272
amd64
job_gcc_py2_amd64

02:56:15