Fully quote guards used by neverclaims.
Especially with should write !(p0) and not !p0, because p0 is usually #define'd by the user and he may have forgotten to quote the value of the macro. This issue was discovered by Kristin Yvonne Rozier and diagnosed by Gerard Holzmann. * src/tgbaalgos/neverclaim.cc (process_link): Call to_spin_string(..., true) to fully parentheses the string. * src/tgbatest/neverclaimread.test: Add a test.