Fix bad C bind name for opencoarrays_co_reduce

 - *Beleived* to be a bug on the 1.x branch, fixed here
 - Correct version appears to be on the master branch

Author: zbeekman

src/extensions/opencoarrays.F90

@@ -220,7 +220,7 @@ subroutine opencoarrays_co_reduce(a, opr, opr_flags, result_image, stat, errmsg,
 #ifdef COMPILER_SUPPORTS_CAF_INTRINSICS
       bind(C,name="_caf_extensions_co_reduce")
 #else
-      bind(C,name="_gfortran_extensions_co_reduce")
+      bind(C,name="_gfortran_caf_co_reduce")
 #endif
       use iso_c_binding, only : c_ptr,c_funptr,c_int,c_char
       type(c_ptr), intent(in), value :: a