[UWP] Fix Error about an undefined Exception for the Promise returned by Present() (#177)

Author: leoek

windows/ReactNativePSPDFKit/ReactNativePSPDFKit/PSPDFKitModule.cs

@@ -68,7 +68,7 @@ public void Present(string assetPath, IPromise promise)
 
                     promise.Resolve(null);
                 }
-                catch (Exception)
+                catch (Exception e)
                 {
                     promise.Reject(e);
                 }