ctest_build: Fix logic regression in parent that clips build output

The sweeping pattern change in commit 238dd2fb (Use insert instead of a
loop in some cases, 2014-11-22) accidentally changed the iterator range
used on the queue in cmCTestBuildHandler::ProcessBuffer.  Instead of
ending at the iterator positioned at the next newline to populate
CurrentProcessingLine, it was changed to go to the end of the queue.
This causes the line to contain newlines and possibly be cut off in the
middle of a line.  Fix this regression by restoring use of the proper
end-of-line position.

Source/CTest/cmCTestBuildHandler.cxx

@@ -1095,7 +1095,7 @@ void cmCTestBuildHandler::ProcessBuffer(const char* data, int length,
       // Create a contiguous array for the line
       this->CurrentProcessingLine.clear();
       this->CurrentProcessingLine.insert(this->CurrentProcessingLine.end(),
-                                         queue->begin(), queue->end());
+                                         queue->begin(), it);
       this->CurrentProcessingLine.push_back(0);
       const char* line = &*this->CurrentProcessingLine.begin();