Currently, the following compilation warning is generated with GCC
version 8.2.1:

In file included from ../src/node_buffer.cc:29:
../src/string_search.h:
In function ‘size_t node::stringsearch::SearchString(
    node::stringsearch::Vector<const Char>,
    node::stringsearch::Vector<const Char>,
    size_t) [with Char = short unsigned int]’:
../src/string_search.h:113:30: warning:
‘search’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
     return (this->*strategy_)(subject, index);
            ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~

../src/string_search.h:
In function ‘size_t node::stringsearch::SearchString(
    node::stringsearch::Vector<const Char>,
    node::stringsearch::Vector<const Char>,
    size_t) [with Char = unsigned char]’:
../src/string_search.h:113:30:
warning: ‘search’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
     return (this->*strategy_)(subject, index);
            ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~

The issue here seems to be with the `strategy_` field which is a pointer
to a member function, and it is set in the constructor of StringSearch.
It is always set and I've not been able to work around this warning
so this commit suggests adding a pragma for GCC to ignore the warning.

This reverts commit b520c74.

Currently, the following compilation warning is generated with GCC
version 8.2.1:

In file included from ../src/node_buffer.cc:29:
../src/string_search.h:
In function ‘size_t node::stringsearch::SearchString(
    node::stringsearch::Vector<const Char>,
    node::stringsearch::Vector<const Char>,
    size_t) [with Char = short unsigned int]’:
../src/string_search.h:113:30: warning:
‘search’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
     return (this->*strategy_)(subject, index);
            ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~

../src/string_search.h:
In function ‘size_t node::stringsearch::SearchString(
    node::stringsearch::Vector<const Char>,
    node::stringsearch::Vector<const Char>,
    size_t) [with Char = unsigned char]’:
../src/string_search.h:113:30:
warning: ‘search’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
     return (this->*strategy_)(subject, index);
            ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~

I'm not sure why this works but delegating to the default constructor of
the base class StringSearchBase makes this warning go away.