Can't build with --with-valgrind

[Lee Bieber]

When configuring with --with-valgrind option we get the following build error:

CXX    drizzled/function/min_max.o
cc1plus: warnings being treated as errors
drizzled/filesort.cc: In member function 'void drizzled::SortParam::make_sortkey(unsigned char*, unsigned char*)':
drizzled/filesort.cc:990: error: declaration of 'end' shadows a member of 'this' [-Wshadow]
make[2]: *** [drizzled/filesort.o] Error 1

[Monty Taylor (mordred)]

I can take care of this.