repl: clear the interrupt before reading the next line

Otherwise, it will be thrown again during exit when the repl is terminated by
end-of-input after the last command was interrupted.

Change-Id: I8456c47bc36cfb0892efdad5420f318f7e6526d5

src/libcmd/repl.cc

@@ -262,6 +262,8 @@ ReplExitStatus NixRepl::mainLoop()
     std::string input;
 
     while (true) {
+        _isInterrupted = false;
+
         // When continuing input from previous lines, don't print a prompt, just align to the same
         // number of chars as the prompt.
         if (!interacter->getLine(input, input.empty() ? ReplPromptType::ReplPrompt : ReplPromptType::ContinuationPrompt)) {
@@ -424,8 +426,6 @@ ProcessLineResult NixRepl::processLine(std::string line)
     if (line.empty())
         return ProcessLineResult::PromptAgain;
 
-    _isInterrupted = false;
-
     std::string command, arg;
 
     if (line[0] == ':') {