Don't pass -Wlogical-op argument to libclang

KDevelop built against current Clang git main version prints the
following warning each time a KDE C++ file is parsed:
warning: unknown warning option '-Wlogical-op'; did you mean '-Wlong-long'? [-Wunknown-warning-option]

That's because KDECompilerSettings passes to gcc and KDevelop forwards
to libclang the -Wlogical-op command-line argument not supported by
Clang.

KDevelop built against my system Clang 14.0.6 does not print this
warning. Perhaps the verbosity level of runtime warnings is different in
these two Clang versions.