Rename the RPM spec file

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
Remove 'declare' from RPM build script

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
Improve RPM build script with defaults for parameters

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>