Catch and ignore KeyboardInterrupt exception

Per discussion in PR #40 comments. This will prevent a stack dump from littering the output when interrupting script run via Control-C. That was useful to have for a while, but probably is not anymore.

Also, fix up a few corner cases where rc could be used without it having been set.

dish_grpc_influx.py

@@ -311,6 +311,7 @@ def main():
         # ...unless influxdb-python package version is too old
         gstate.influx_client = InfluxDBClient(**opts.icargs)
 
+    rc = 0
     try:
         next_loop = time.monotonic()
         while True:
@@ -321,7 +322,7 @@ def main():
                 time.sleep(next_loop - now)
             else:
                 break
-    except Terminated:
+    except (KeyboardInterrupt, Terminated):
         pass
     finally:
         loop_body(opts, gstate, shutdown=True)

dish_grpc_influx2.py

@@ -307,7 +307,7 @@ def main():
                 time.sleep(next_loop - now)
             else:
                 break
-    except Terminated:
+    except (KeyboardInterrupt, Terminated):
         pass
     finally:
         loop_body(opts, gstate, shutdown=True)

dish_grpc_mqtt.py

@@ -184,6 +184,7 @@ def main():
 
     signal.signal(signal.SIGTERM, handle_sigterm)
 
+    rc = 0
     try:
         next_loop = time.monotonic()
         while True:
@@ -194,11 +195,12 @@ def main():
                 time.sleep(next_loop - now)
             else:
                 break
-    except Terminated:
+    except (KeyboardInterrupt, Terminated):
         pass
     finally:
         gstate.shutdown()
-        sys.exit(rc)
+
+    sys.exit(rc)
 
 
 if __name__ == '__main__':

dish_grpc_sqlite.py

@@ -303,7 +303,7 @@ def main():
     except sqlite3.Error as e:
         logging.error("Database error: %s", e)
         rc = 1
-    except Terminated:
+    except (KeyboardInterrupt, Terminated):
         pass
     finally:
         loop_body(opts, gstate, shutdown=True)

dish_grpc_text.py

@@ -274,6 +274,7 @@ def main():
         sys.exit(1)
     signal.signal(signal.SIGTERM, handle_sigterm)
 
+    rc = 0
     try:
         next_loop = time.monotonic()
         while True:
@@ -284,7 +285,7 @@ def main():
                 time.sleep(next_loop - now)
             else:
                 break
-    except Terminated:
+    except (KeyboardInterrupt, Terminated):
         pass
     finally:
         loop_body(opts, gstate, print_file, shutdown=True)