configure: Fix pylint warnings

Signed-off-by: Euan Harris <euan.harris@citrix.com>
install: Fix undefined variable pylint error

Signed-off-by: Euan Harris <euan.harris@citrix.com>
install: Fix pylint warnings

Signed-off-by: Euan Harris <euan.harris@citrix.com>
configure: Fix remaining pylint warnings

Signed-off-by: Euan Harris <euan.harris@citrix.com>
build: Check subprocess return codes

Pointed out (indirectly) by pylint's unused variable warning.

Signed-off-by: Euan Harris <euan.harris@citrix.com>
build: Extract SRPM build logic into a function

Signed-off-by: Euan Harris <euan.harris@citrix.com>
build: Fix more pylint whitespace warnings

Signed-off-by: Euan Harris <euan.harris@citrix.com>
build: Fix pylint variable name warnings

Signed-off-by: Euan Harris <euan.harris@citrix.com>