Rename ycm's compile command list file name

Rename ".compilation_commands.json" to "compile_commands.json".
Fix inconsistent function name in ycm conf

Signed-off-by: mat tso <mat-tso@topmail.ie>
Correct and improve error message

Signed-off-by: mat tso <mat-tso@topmail.ie>
Deactivate default flag

Signed-off-by: mat tso <mat-tso@topmail.ie>