Ooops, I messed up the stderr file for T5287; this fixes it

testsuite/tests/deriving/should_fail/T5287.stderr

-ghc-stage2.exe: panic! (the 'impossible' happened)
-  (GHC version 7.3.20110721 for i386-unknown-mingw32):
-	solveDerivEqns: probable loop
-    (T5287.hs:6:29-32 main:Bug.$fReadE{v rhW} [e{tv aaR} [tv]] base:GHC.Read.Read{tc 2d} [main:Bug.E{tc raM}
-                                                                                            e{tv aaR} [tv]] = [base:GHC.Read.Read{tc 2d}
-                                                                                                                 (main:Bug.D{tc raO}
-                                                                                                                    e{tv aaR} [tv])])
-    [[main:Bug.A{tc raQ} e{tv aaR} [tv] oops{tv alO} [tcs]]]
-
-Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
 
+T5287.hs:6:29:
+    Ambiguous type variable `oops' in the constraint:
+      (A e oops)
+        arising from the 'deriving' clause of a data type declaration
+    Probable fix: use a 'standalone deriving' declaration instead
+    When deriving the instance for (Read (E e))