mosh-server: Remove unused mosh_read_line function

This function is buggy.  feof(file) does not become true until after
we’ve tried to read past the last character; it should instead be
checking the getc return value for EOF (which is distinct from any
unsigned char).  Really it should just be replaced by istream
&std::getline(istream &is, string &str).  Fortunately, it’s unused so
we can just delete it.

Resolves a truncated stdio return value issue found by Coverity Scan
service.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

src/frontend/mosh-server.cc

@@ -801,19 +801,6 @@ bool device_exists( const char *ut_line )
   return (0 == lstat( device_name.c_str(), &buf ));
 }
 
-string mosh_read_line( FILE *file )
-{
-  string ret;
-  while ( !feof( file ) ) {
-    char next = getc( file );
-    if ( next == '\n' ) {
-      return ret;
-    }
-    ret.push_back( next );
-  }
-  return ret;
-}
-
 void warn_unattached( const string & ignore_entry )
 {
 #ifdef HAVE_UTMPX_H