test/py: efi_capsule: align with efidebug syntax changes

After the commit c70f4481 ("efi_loader: simplify 'printenv -e'"),
"-all" option is no longer necessary.
Just remove them in the test script.

Fixes: c70f4481 ("efi_loader: simplify 'printenv -e'")
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>