Fixes "Use of uninitialized value $ScanView in exec" error on systems with scan-view executable not located in the expected place.
Currently when scan-build is installed in Debian-like (Ubuntu 18.04 my case) system the scan-view executable is not correctly identified when installed by apt from clang-tools package.
The buggy code was first introduced here 10 ago:
The issue was recently reported on Debian Bugs:
The problem lies in current master scan-build:974:
Searching for "$RealBin/../../scan-view/bin/scan-view" may not work in such cases because directories are versioned e.g. "$RealBin/../../scan-view-6.0/bin/scan-view".