[patches] update README

(cherry picked from commit 3e93ea7b)

patches/README

@@ -6,15 +6,13 @@
 
 - If opm-grid has to be used for, e.g., employing the CpGridCreator,
   and Opm is compiled from source, it might be necessary to patch opm-parser and opm-common:
-  patch -p1 <../dumux/patches/opm-parser-2016.04.patch
-  patch -p1 <../dumux/patches/opm-common-2016.04.patch
+  patch -p1 <../dumux/patches/opm-parser-2017.10.patch
+  patch -p1 <../dumux/patches/opm-common-2017.10.patch
   In addition, it might be necessary to set manually some CMake variables in the
   CMAKE_FLAGS section of the .opts-file:
     -DOPM_COMMON_ROOT=/path/to/opm-common/ \
     -Dopm-grid_PREFIX=/path/to/opm-grid \
     -Dopm-common_PREFIX=/path/to/opm-common \
-    -Dopm-core_PREFIX=/path/to/opm-core \
-    -Dopm-material_PREFIX=/path/to/opm-material \
     -Dopm-parser_PREFIX=/path/to/opm-parser \
     -DHAVE_OPM_GRID=1 \
-  Currently, Dumux is supposed to be compatible with the Opm 2016.04 release.
+  Currently, Dumux is supposed to be compatible with the Opm 2017.04 and 2017.10 releases.