Rename build logs and make names consistent (#11806)

Fixes #11781

* Rename build log to spack-build-log.txt
* Rename environment variables file to spack-build-env.txt
* The name of the log and env files is now the same during the build
  and after the build completes
* Update packages which referred to the build log/env files
* For packages installed before this commit using older names for the
  build and env files, search for the older names

var/spack/repos/builtin/packages/foam-extend/package.py

@@ -425,7 +425,7 @@ def install_links(self):
         # Make build log visible - it contains OpenFOAM-specific information
         with working_dir(self.projectdir):
             os.symlink(
-                join_path('.spack', 'build.out'),
+                join_path(os.path.relpath(self.install_log_path)),
                 join_path('log.' + str(self.foam_arch)))
 
 # -----------------------------------------------------------------------------

var/spack/repos/builtin/packages/mathematica/package.py

@@ -29,11 +29,3 @@ def install(self, spec, prefix):
            '-targetdir={0}'.format(prefix),
            '-execdir={0}'.format(prefix.bin),
            '-selinux=y')
-
-        # after the install phase completes, spack tries to install build.out
-        # into <prefix>/.spack, but the .spack dir will not exist, causing the
-        # build to fail. package.py:1690 seems to show that the dir is created
-        # right before writing build.out -- possible bug?
-
-        # creating the .spack dir right after installing prevents explosions
-        mkdirp(join_path(prefix, '.spack'))

var/spack/repos/builtin/packages/openfoam-org/package.py

@@ -344,7 +344,7 @@ def install_links(self):
         # Make build log visible - it contains OpenFOAM-specific information
         with working_dir(self.projectdir):
             os.symlink(
-                join_path('.spack', 'build.out'),
+                join_path(os.path.relpath(self.install_log_path)),
                 join_path('log.' + str(self.foam_arch)))
 
         if not self.config['link']:

var/spack/repos/builtin/packages/openfoam/package.py

@@ -724,7 +724,7 @@ def install_links(self):
         # Make build log visible - it contains OpenFOAM-specific information
         with working_dir(self.projectdir):
             os.symlink(
-                join_path('.spack', 'build.out'),
+                join_path(os.path.relpath(self.install_log_path)),
                 join_path('log.' + str(self.foam_arch)))
 
         if not self.config['link']:

var/spack/repos/builtin/packages/picard/package.py

@@ -42,7 +42,7 @@ class Picard(Package):
     def install(self, spec, prefix):
         mkdirp(prefix.bin)
         # The list of files to install varies with release...
-        # ... but skip the spack-{build.env}.out files.
+        # ... but skip the spack-build-{env}out.txt files.
         files = [x for x in glob.glob("*") if not re.match("^spack-", x)]
         for f in files:
             install(f, prefix.bin)