[SCons] Correct install locations in post-install message

SConstruct

@@ -2016,9 +2016,9 @@ def postInstallMessage(target, source, env):
 
         File locations:
 
-          applications                {ct_bindir!s}
-          library files               {ct_libdir!s}
-          C++ headers                 {ct_incroot!s}
+          applications                {inst_bindir!s}
+          library files               {inst_libdir!s}
+          C++ headers                 {inst_incroot!s}
           samples                     {inst_sampledir!s}
           data files                  {inst_datadir!s}""".format(**env_dict))
 
@@ -2036,22 +2036,23 @@ def postInstallMessage(target, source, env):
             minimal Python module       {python_module_loc!s}""".format(**env_dict)), '  ')
 
     if env['matlab_toolbox'] == 'y':
-        env['matlab_sample_loc'] = pjoin(env['ct_sampledir'], 'matlab')
-        env['matlab_ctpath_loc'] = pjoin(env['ct_matlab_dir'], 'ctpath.m')
+        env["matlab_sample_loc"] = pjoin(env["inst_sampledir"], "matlab")
+        env["matlab_ctpath_loc"] = pjoin(env["inst_matlab_dir"], "ctpath.m")
         install_message += textwrap.dedent("""
-              Matlab toolbox              {ct_matlab_dir!s}
+              Matlab toolbox              {inst_matlab_dir!s}
               Matlab samples              {matlab_sample_loc!s}
 
             An m-file to set the correct matlab path for Cantera is at:
 
               {matlab_ctpath_loc!s}
         """.format(**env_dict))
+    else:
+        install_message += "\n"
 
     if os.name != 'nt':
         env['setup_cantera'] = pjoin(env['ct_bindir'], 'setup_cantera')
         env['setup_cantera_csh'] = pjoin(env['ct_bindir'], 'setup_cantera.csh')
         install_message += textwrap.dedent("""
-
             Setup scripts to configure the environment for Cantera are at:
 
               setup script (bash)         {setup_cantera!s}
@@ -2062,6 +2063,7 @@ def postInstallMessage(target, source, env):
               source {setup_cantera!s}
 
             before using Cantera, or else include its contents in your shell login script.
+
         """.format(**env_dict))
 
     print(install_message)