postgresql: update source to 9.5.1 and refresh patches

Setting the additional include path for host-build of ecpg is no
longer required and started breaking the build (PostgeSQL BUG-14033),
remove it.
Also, pgsql-server no longer requires shadow-su since procd can take
care of starting it running under the appropriate user.
Moving the dependency to pgsql-cli makes sense as the 'su' command is
still needed to boot-strap a new data directory and also commonly used
for other administration tasks. However, in that way the CLI and
shadow-su can be removed during production once pgsql-server has been
setup.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

libs/postgresql/patches/800-busybox-default-pager.patch

@@ -1,8 +1,8 @@
 --- a/src/bin/psql/print.h
 +++ b/src/bin/psql/print.h
-@@ -179,10 +179,6 @@ extern void printQuery(const PGresult *r
- extern void setDecimalLocale(void);
+@@ -197,10 +197,6 @@ extern void setDecimalLocale(void);
  extern const printTextFormat *get_line_style(const printTableOpt *opt);
+ extern void refresh_utf8format(const printTableOpt *opt);
  
 -#ifndef __CYGWIN__
 -#define DEFAULT_PAGER "more"