Remove relative path so -I$PETSC_DIR/include finds installed headers

Index: petsc/src/mat/examples/tests/ex110.c
===================================================================
--- petsc.orig/src/mat/examples/tests/ex110.c
+++ petsc/src/mat/examples/tests/ex110.c
@@ -1,7 +1,7 @@
 static char help[] = "Testing MatCreateMPIAIJWithSplitArrays().\n\n";
 
 #include <petscmat.h>
-#include <../src/mat/impls/aij/mpi/mpiaij.h>
+#include <src/mat/impls/aij/mpi/mpiaij.h>
 
 #undef __FUNCT__
 #define __FUNCT__ "main"
Index: petsc/src/mat/examples/tutorials/ex4.c
===================================================================
--- petsc.orig/src/mat/examples/tutorials/ex4.c
+++ petsc/src/mat/examples/tutorials/ex4.c
@@ -89,7 +89,7 @@ int main(int argc,char **args)
   return 0;
 }
 
-#include <../src/mat/impls/dense/mpi/mpidense.h>
+#include <src/mat/impls/dense/mpi/mpidense.h>
 
 #undef __FUNCT__
 #define __FUNCT__ "LowRankUpdate"