[usb] improve usb storage

° when an usb is plugged, wait for an usb-storage cnxion, then
  stop the autopilot to reserve cp for usb-storage thread.
  Yes, we should avoid false detection, so there is two level of detection
  before shutting down autopilot thread.

remove spurious white char @ eol

conf/Makefile.chibios-libopencm3

@@ -37,12 +37,12 @@ endif
 #
 # This is the common Makefile for target using chibios
 
-
 CHIBIOS_BOARD_DIR = $(PAPARAZZI_SRC)/sw/airborne/boards/$(BOARD)/chibios-libopencm3
 CHIBIOS_LIB_DIR = $(PAPARAZZI_SRC)/sw/airborne/subsystems/chibios-libopencm3
 CHIBIOS_EXT =  $(PAPARAZZI_SRC)/sw/ext/chibios
 OPENCM3_EXT =  $(PAPARAZZI_SRC)/sw/ext/libopencm3
 PPRZ_GENERATED = $(PAPARAZZI_SRC)/var/$(AIRCRAFT)/generated
+PPRZ_CHIBIOS_OCM3 = $(SRC_FIRMWARE)/chibios-libopencm3
 
 # Launch with "make Q=''" to get full command display
 Q=@
@@ -208,7 +208,8 @@ INCDIR = $(PORTINC) $(KERNINC) $(TESTINC) \
          $(HALINC) $(PLATFORMINC) $(BOARDINC) \
          $(CHIBIOS)/os/various $(OPENCM3_INC) \
 	 $(CHIBIOS_BOARD_DIR) $(CHIBIOS_LIB_DIR) \
-	 $(PPRZ_GENERATED) $(FATFSINC)
+	 $(PPRZ_GENERATED) $(FATFSINC) \
+	 $(PPRZ_CHIBIOS_OCM3)
 
 BUILDDIR := $(OBJDIR)
 #