nightly: the path to yaml templates is relative

Don't prefix the path to the yaml templates - the nightly template
itself is already in the `azure-pipelines` directory.  Instead, just
use the relative path.

azure-pipelines/nightly.yml

@@ -7,7 +7,7 @@ jobs:
   pool:
     vmImage: 'Ubuntu 16.04'
   steps:
-  - template: azure-pipelines/docker.yml
+  - template: docker.yml
     parameters:
       imageName: 'libgit2/trusty-amd64:latest'
       environmentVariables: |
@@ -20,7 +20,7 @@ jobs:
   pool:
     vmImage: 'Ubuntu 16.04'
   steps:
-  - template: azure-pipelines/docker.yml
+  - template: docker.yml
     parameters:
       imageName: 'libgit2/trusty-amd64:latest'
       environmentVariables: |
@@ -33,7 +33,7 @@ jobs:
   pool:
     vmImage: 'Ubuntu 16.04'
   steps:
-  - template: azure-pipelines/docker.yml
+  - template: docker.yml
     parameters:
       imageName: 'libgit2/trusty-amd64:latest'
       environmentVariables: |
@@ -46,7 +46,7 @@ jobs:
   pool:
     vmImage: 'Ubuntu 16.04'
   steps:
-  - template: azure-pipelines/docker.yml
+  - template: docker.yml
     parameters:
       imageName: 'libgit2/trusty-amd64:latest'
       environmentVariables: |
@@ -61,7 +61,7 @@ jobs:
   steps:
   - bash: . '$(Build.SourcesDirectory)/ci/setup-osx.sh'
     displayName: Setup
-  - template: azure-pipelines/bash.yml
+  - template: bash.yml
     parameters:
       environmentVariables:
         TMPDIR: $(Agent.TempDirectory)
@@ -73,7 +73,7 @@ jobs:
   displayName: 'Windows (amd64; Visual Studio)'
   pool: Hosted
   steps:
-  - template: azure-pipelines/powershell.yml
+  - template: powershell.yml
     parameters:
       environmentVariables:
         CMAKE_OPTIONS: -DMSVC_CRTDBG=ON -G"Visual Studio 12 2013 Win64"
@@ -82,7 +82,7 @@ jobs:
   displayName: 'Windows (x86; Visual Studio)'
   pool: Hosted
   steps:
-  - template: azure-pipelines/powershell.yml
+  - template: powershell.yml
     parameters:
       environmentVariables:
         CMAKE_OPTIONS: -DMSVC_CRTDBG=ON -G"Visual Studio 12 2013"
@@ -96,7 +96,7 @@ jobs:
     env:
       TEMP: $(Agent.TempDirectory)
       ARCH: amd64
-  - template: azure-pipelines/powershell.yml
+  - template: powershell.yml
     parameters:
       environmentVariables:
         CMAKE_OPTIONS: -G"MinGW Makefiles"
@@ -112,7 +112,7 @@ jobs:
     env:
       TEMP: $(Agent.TempDirectory)
       ARCH: x86
-  - template: azure-pipelines/powershell.yml
+  - template: powershell.yml
     parameters:
       environmentVariables:
         CMAKE_OPTIONS: -G"MinGW Makefiles"