gitweb: Set default destination directory for installing gitweb in Makefile
gitweb: Set default destination directory for installing gitweb in Makefile

Currently installing gitweb requires to give a target directory
(via 'gitwebdir' build variable).  Giving it a default value
protects against user errors.

Signed-off-by: Pavan Kumar Sunkara <1b5e356bb84465e3deee937143bf6a83a050649c@gmail.com>
Mentored-by: Christian Couder <ddbaab5867ed34fd53535b58c9cdd59abd2e2aff@tuxfamily.org>
Mentored-by: Petr Baudis <2df6472652419df7dced808d07835f28963a653f@ucw.cz>
Acked-by: Jakub Narebski <a6a1517a087f9f64a72f41a0de57ff01fbb0e412@gmail.com>
Acked-by: Petr Baudis <2df6472652419df7dced808d07835f28963a653f@suse.cz>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git