As recommended by pylint:

  boot-qemu.py:698:12: R1722: Consider using sys.exit() (consider-using-sys-exit)
  utils.py:29:4: R1722: Consider using sys.exit() (consider-using-sys-exit)

Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Cleans up the following pylint warnings:

  utils.py:55:11: R1714: Consider merging these comparisons with 'in' by using 'image in ('vmlinux', 'linux')'. Use a set instead if elements are hashable. (consider-using-in)
  boot-qemu.py:124:19: R1714: Consider merging these comparisons with 'in' by using 'guest_arch in ('arm', 'arm32_v7')'. Use a set instead if elements are hashable. (consider-using-in)
  boot-qemu.py:404:9: R1714: Consider merging these comparisons with 'in' by using 'arch in ('arm', 'arm32_v7')'. Use a set instead if elements are hashable. (consider-using-in)
  boot-qemu.py:414:9: R1714: Consider merging these comparisons with 'in' by using 'arch in ('arm64', 'arm64be')'. Use a set instead if elements are hashable. (consider-using-in)
  boot-qemu.py:456:9: R1714: Consider merging these comparisons with 'in' by using 'arch in ('mips', 'mipsel')'. Use a set instead if elements are hashable. (consider-using-in)

Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Helps compact code and eliminate the following pylint warnings:

  boot-qemu.py:132:21: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
  boot-qemu.py:132:46: C0103: Variable name "f" doesn't conform to snake_case naming style (invalid-name)

Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Elminate the following pylint warnings:

  boot-qemu.py:190:13: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
  boot-qemu.py:190:34: C0103: Variable name "f" doesn't conform to snake_case naming style (invalid-name)

Signed-off-by: Nathan Chancellor <nathan@kernel.org>

As suggested by pylint:

  boot-qemu.py:666:27: R1732: Consider using 'with' for resource-allocating operations (consider-using-with)

This allows us to drop the explicit call to wait(), as the exit path for
Popen() as a context manager automatically calls wait().

Signed-off-by: Nathan Chancellor <nathan@kernel.org>

An explicit check parameter is recommended to make it obvious what the
error handling is. Cleans up the following pylint warnings:

  boot-qemu.py:127:39: W1510: Using subprocess.run without explicitly set `check` is not recommended. (subprocess-run-check)
  boot-qemu.py:659:19: W1510: Using subprocess.run without explicitly set `check` is not recommended. (subprocess-run-check)
  boot-qemu.py:672:16: W1510: Using subprocess.run without explicitly set `check` is not recommended. (subprocess-run-check)

Signed-off-by: Nathan Chancellor <nathan@kernel.org>

As recommended by pylint:

  boot-uml.py:47:4: W0621: Redefining name 'rootfs' from outer scope (line 80) (redefined-outer-name)
  boot-uml.py:60:15: W0621: Redefining name 'kernel' from outer scope (line 79) (redefined-outer-name)
  boot-uml.py:60:23: W0621: Redefining name 'rootfs' from outer scope (line 80) (redefined-outer-name)
  boot-qemu.py:141:18: W0621: Redefining name 'args' from outer scope (line 703) (redefined-outer-name)
  boot-qemu.py:202:14: W0621: Redefining name 'args' from outer scope (line 703) (redefined-outer-name)
  boot-qemu.py:322:26: W0621: Redefining name 'cfg' from outer scope (line 706) (redefined-outer-name)
  boot-qemu.py:356:18: W0621: Redefining name 'cfg' from outer scope (line 706) (redefined-outer-name)
  boot-qemu.py:632:16: W0621: Redefining name 'cfg' from outer scope (line 706) (redefined-outer-name)

As it turns out, this caught a bug in can_use_kvm(), where args was
being used without being passed into the function.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>