remove Vim and Emacs variable settings from C source files

Done with these commands:
git grep -l Local.variab|xargs \
  perl -0x3b -pi -e 's,\n+/\*\n \* vim:(.|\n)*,\n,'

git grep -l Local.variab|xargs \
  perl -0x3b -pi -e 's,\n+/\*\n \* Local variables:\n(.|\n)*,\n,'

tests/testutils.c

@@ -206,13 +206,3 @@ int virtTestCaptureProgramOutput(const char *const argv[],
         }
     }
 }
-
-
-/*
- * Local variables:
- *  indent-tabs-mode: nil
- *  c-indent-level: 4
- *  c-basic-offset: 4
- *  tab-width: 4
- * End:
- */