Clean up compilation warnings.

../../../src/CLI/CLI.cs(147,29): warning CS0168: The variable `ex' is declared but never used
../../../src/CLI/CLI.cs(186,30): warning CS0168: The variable `ex' is declared but never used

src/CLI/CLI.cs

@@ -144,7 +144,7 @@ namespace CppSharp
                     messages.Add(String.Format("File {0} doesn't exist. Not adding to the list of files to generate bindings from.", args));
                 }
             }
-            catch(Exception ex)
+            catch(Exception)
             {
                 messages.Add(String.Format("Error while looking for files inside path {0}. Ignoring.", args));
             }
@@ -183,7 +183,7 @@ namespace CppSharp
                         options.HeaderFiles.Add(s);
                 }
             }
-            catch (Exception ex)
+            catch (Exception)
             {
                 messages.Add(String.Format("Error while looking for files inside path {0}. Ignoring.", path));
             }