BUG: Fix preprocess and assembly rule expansion

The recent change to avoid expanding rule variables in informational and
'cd' commands broke the logical order in generation of preprocess and
assembly rules.  This corrects the order.

Source/cmMakefileTargetGenerator.cxx

@@ -724,6 +724,12 @@ cmMakefileTargetGenerator
         std::vector<std::string> preprocessCommands;
         cmSystemTools::ExpandListArgument(preprocessRule, preprocessCommands);
 
+        std::string shellObjI =
+          this->Convert(objI.c_str(),
+                        cmLocalGenerator::NONE,
+                        cmLocalGenerator::SHELL).c_str();
+        vars.PreprocessedSource = shellObjI.c_str();
+
         // Expand placeholders in the commands.
         for(std::vector<std::string>::iterator i = preprocessCommands.begin();
             i != preprocessCommands.end(); ++i)
@@ -738,12 +744,6 @@ cmMakefileTargetGenerator
         commands.insert(commands.end(),
                         preprocessCommands.begin(),
                         preprocessCommands.end());
-
-        std::string shellObjI =
-          this->Convert(objI.c_str(),
-                        cmLocalGenerator::NONE,
-                        cmLocalGenerator::SHELL).c_str();
-        vars.PreprocessedSource = shellObjI.c_str();
         }
       else
         {
@@ -781,6 +781,12 @@ cmMakefileTargetGenerator
         std::vector<std::string> assemblyCommands;
         cmSystemTools::ExpandListArgument(assemblyRule, assemblyCommands);
 
+        std::string shellObjS =
+          this->Convert(objS.c_str(),
+                        cmLocalGenerator::NONE,
+                        cmLocalGenerator::SHELL).c_str();
+        vars.AssemblySource = shellObjS.c_str();
+
         // Expand placeholders in the commands.
         for(std::vector<std::string>::iterator i = assemblyCommands.begin();
             i != assemblyCommands.end(); ++i)
@@ -795,12 +801,6 @@ cmMakefileTargetGenerator
         commands.insert(commands.end(),
                         assemblyCommands.begin(),
                         assemblyCommands.end());
-
-        std::string shellObjS =
-          this->Convert(objS.c_str(),
-                        cmLocalGenerator::NONE,
-                        cmLocalGenerator::SHELL).c_str();
-        vars.AssemblySource = shellObjS.c_str();
         }
       else
         {