jtag: Fix jtag_reset fallback

jtag: Fix jtag_reset fallback

The fallback provided for the jtag_reset command always fails with a
strange message: 'Error: invalid command name "de"'

This is caused by incorrect quoting inside the warning message.

Fixes: c07b774e8f49 ("jtag: replace command "jtag_reset" with "adapter [de]assert"")
Change-Id: Icd47fca2b5a7b33474bfb0040e88193a0968f301
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Reviewed-on: http://openocd.zylin.com/5416
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>