Fix build error when (ADB|FASTBOOT)_VERSION has space

Test: make, and build pass
Change-Id: I8fc608a5b8bccb43b8af72978ce16a945147f62d
diff --git a/fastboot/Android.mk b/fastboot/Android.mk
index 4d54175..80def73 100644
--- a/fastboot/Android.mk
+++ b/fastboot/Android.mk
@@ -18,7 +18,7 @@
 
 include $(CLEAR_VARS)
 
-LOCAL_CFLAGS += -DFASTBOOT_VERSION=\"$(tool_version)\"
+LOCAL_CFLAGS += -DFASTBOOT_VERSION="\"$(tool_version)\""
 
 LOCAL_C_INCLUDES := \
   $(LOCAL_PATH)/../adb \