minor fix in the cmake file for python

Former-commit-id: c61282f6a1a1b1d14aec233e9f9ff167716474b5

python/CMakeLists.txt

@@ -62,7 +62,7 @@ option(LIBIGL_WITH_LIM              "Use LIM"            ON)
 option(LIBIGL_WITH_MATLAB           "Use Matlab"         OFF)
 option(LIBIGL_WITH_MOSEK            "Use MOSEK"          OFF)
 option(LIBIGL_WITH_BBW              "Use BBW"            ON)
-option(LIBIGL_WITH_OPENGL_AND_PNG   "Use OpenGL"         ON)
+option(LIBIGL_WITH_PNG              "Use PNG"            ON)
 option(LIBIGL_WITH_TETGEN           "Use Tetgen"         ON)
 option(LIBIGL_WITH_TRIANGLE         "Use Triangle"       ON)
 option(LIBIGL_WITH_XML              "Use XML"            ON)
@@ -190,4 +190,3 @@ elseif (UNIX)
     endif()
   endif()
 endif()
-