run-tests: fixes the '--interactive' option error

This patch fixes a regression recently introduced by a refactoring.

Previously when failure occurs while testing with '--interactive' was enable,
it didn't prompt user by asking whether he wants to accept this failure
changes or not.

This was happening beacuse of the 'if' condition
if ret or not self._options.interactive or \
not os.path.exists(test.errpath):

Everytime failure occurs, this condition gets true and returns back even
when '--interactive' is enabled. This condition don't led the function to
execute further, which consist the '--interactive' functionality.

Now, on failure with '--interactive' enabled, it prompts user whether he wants
to accepts failure changes or not.
If yes then test gets passed  and returns true, else test gets failed.

On every failure, results gets stored in "self.failures.append((test, reason))"
But if failure changes accepted by user then test must get "pop out" from
failed test list.

tests/run-tests.py

@@ -1083,6 +1083,20 b' class TestResult(unittest._TextTestResul'
         else:
             if not self._options.nodiff:
                 self.stream.write('\nERROR: %s output changed\n' % test)
+
+            if self._options.interactive:
+                iolock.acquire()
+                self.stream.write('Accept this change? [n] ')
+                answer = sys.stdin.readline().strip()
+                iolock.release()
+                if answer.lower() in ('y', 'yes'):
+                    if test.name.endswith('.t'):
+                        rename(test.errpath, test.path)
+                    else:
+                        rename(test.errpath, '%s.out' % test.path)
+                    self.failures.pop()
+                    return 1
+
             self.stream.write('!')
 
     def addError(self, *args, **kwargs):
@@ -1146,16 +1160,6 b' class TestResult(unittest._TextTestResul'
             not os.path.exists(test.errpath):
             return
 
-        iolock.acquire()
-        print 'Accept this change? [n] ',
-        answer = sys.stdin.readline().strip()
-        iolock.release()
-        if answer.lower() in ('y', 'yes'):
-            if test.name.endswith('.t'):
-                rename(test.errpath, test.path)
-            else:
-                rename(test.errpath, '%s.out' % test.path)
-
     def startTest(self, test):
         super(TestResult, self).startTest(test)