[symbolizer] Change error message if module not found

If llvm-symbolize did not find module, the error looked like:

    LLVMSymbolizer: error reading file: No such file or directory

This message does not follow common practice: LLVMSymbolizer is not an
utility name. Also the message did not not contain the name of missed file.

With this change the error message looks differently:

    llvm-symbolizer: error: 'abc': No such file or directory

This format is closer to messages produced by other utilities and allow
proper coloring.

Differential Revision: https://reviews.llvm.org/D148032