python3: Update to version 3.7.4

- Update setuptools to 40.8.0
- Update pip to 19.0.3
- Refreshed patches
- Removed 4 patches (2 of them was included in 3.7.3 and other two are
included in this release)

Makefile python3:
- Move PKG_MAINTAINER above PKG_LICENSE

Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>

lang/python/python3/patches/014-remove-platform-so-suffix.patch

@@ -1,6 +1,6 @@
 --- a/configure
 +++ b/configure
-@@ -15129,7 +15129,7 @@ $as_echo_n "checking ABIFLAGS... " >&6;
+@@ -15273,7 +15273,7 @@ $as_echo_n "checking ABIFLAGS... " >&6;
  $as_echo "$ABIFLAGS" >&6; }
  { $as_echo "$as_me:${as_lineno-$LINENO}: checking SOABI" >&5
  $as_echo_n "checking SOABI... " >&6; }
@@ -11,7 +11,7 @@
  
 --- a/configure.ac
 +++ b/configure.ac
-@@ -4719,7 +4719,7 @@ AC_SUBST(SOABI)
+@@ -4736,7 +4736,7 @@ AC_SUBST(SOABI)
  AC_MSG_CHECKING(ABIFLAGS)
  AC_MSG_RESULT($ABIFLAGS)
  AC_MSG_CHECKING(SOABI)