Fix indent type

Author: Blueve

slave.mk

@@ -802,7 +802,7 @@ $(addprefix $(TARGET_PATH)/, $(SONIC_INSTALLERS)) : $(TARGET_PATH)/% : \
                 $(LIBPAM_TACPLUS) \
                 $(LIBNSS_TACPLUS) \
                 $(MONIT) \
-				$(OPENSSH_SERVER) \
+                $(OPENSSH_SERVER) \
                 $(PYTHON_SWSSCOMMON) \
                 $(PYTHON3_SWSSCOMMON) \
                 $(SONIC_UTILITIES_DATA) \