Revert "Workaround compilation problems on gcc 4.6.0"

This reverts commit eac0cc35.

gcc is "incompatible" from version to version in accepted parameters.

slapos/profile/memcached.cfg

@@ -40,8 +40,6 @@ patches =
   ${memcached-strict-aliasing-patch:location}/${memcached-strict-aliasing-patch:filename}
   ${memcached-fix-array-subscript-is-above-array-bounds:location}/${memcached-fix-array-subscript-is-above-array-bounds:filename}
 patch-options = -p1
-# CFLAGS=-Wno-error=unused-but-set-variable allows to compile on gcc 4.6.0
-# http://code.google.com/p/memcached/issues/detail?id=199
 environment =
-    CFLAGS=-Wno-error=unused-but-set-variable
     LDFLAGS =-Wl,-rpath ${libevent:location}/lib
+