DOLFIN fails to pick up slepc4py

[Johannes Ring]

This can be seen on both bamboo and on pipelines:

build   12-Nov-2016 14:05:26    -- Checking for package 'SLEPc4Py'
build   12-Nov-2016 14:05:26    -- slepc4py version 3.7.0 found
build   12-Nov-2016 14:05:26    -- Found SLEPc4py: /usr/local/lib/python2.7/dist-packages/slepc4py/include  
error   12-Nov-2016 14:05:26    CMake Warning at CMakeLists.txt:477 (message):
error   12-Nov-2016 14:05:26      SLEPc version 3.7.3 and slepc4py version 3.7.0 do not match.  Disabling
error   12-Nov-2016 14:05:26      slepc4py support
error   12-Nov-2016 14:05:26    
error   12-Nov-2016 14:05:26    

[Prof Garth Wells]

Fix typo in SLEPc version deteection. Fixes #783.

→ <<cset febf677c4fae>>