treewide: remove redundant quotes

pkgs/development/tools/ocaml/camlidl/default.nix

@@ -44,7 +44,7 @@ stdenv.mkDerivation rec {
 
   meta = {
     description = "A stub code generator and COM binding for Objective Caml";
-    homepage = "${webpage}";
+    homepage = webpage;
     license = "LGPL";
     maintainers = [ stdenv.lib.maintainers.roconnor ];
   };

pkgs/development/tools/ocaml/cppo/default.nix

@@ -44,7 +44,7 @@ stdenv.mkDerivation ({
     longDescription = ''
       Cppo is an equivalent of the C preprocessor targeted at the OCaml language and its variants.
     '';
-    homepage = "${webpage}";
+    homepage = webpage;
     maintainers = [ maintainers.vbgl ];
     license = licenses.bsd3;
   };

pkgs/development/tools/ocaml/omake/0.9.8.6-rc1.nix

@@ -36,7 +36,7 @@ stdenv.mkDerivation {
 
   meta = {
     description = "Omake build system";
-    homepage = "${webpage}";
+    homepage = webpage;
     license = "GPL";
     platforms = ocaml.meta.platforms or [];
   };